The use of geoscience methods for terrestrial forensic searches

Pringle, J.K.1*, Ruffell, A.2, Jervis, J.R.1, Donnelly, L.3, McKinley, J.2, Hansen, J.1,

Morgan, R.4, Pirrie, D.5 & Harrison, M.6,7

1School of Physical Sciences & Geography, Keele University, Keele, Staffs., ST5

5BG, UK.

2School of Geography, Archaeology and Palaeoecology, Queen’s University, Belfast,

BT7 1NN, UK.

3Wardell Armstrong LLP, 2, The Avenue, Leigh, Greater Manchester, WN7 1ES, UK.

4Department of Security and Crime Science and UCL JDI Centre for the Forensic

Sciences, University College London, 35, Tavistock Square, London, WC1H 9EZ,

UK.

5Helford Geoscience LLP, Menallack Farm, Treverva, Penryn, Cornwall, TR10 9BP,

UK.

6Commander Forensic Operations, Australian Federal Police, GPO Box 401,

Canberra, ACT 2601, Australia.

7Faculty of Applied Science, Building 3, University of Canberrra, ACT 2601,

Australia.

Corresponding author: Jamie Pringle.

Email: j.k.pringle@esci.keele.ac.uk Fax: +44 (0)1782 733737

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Abstract

Geoscience methods are increasingly being utilised in criminal, environmental and

humanitarian forensic investigations, and the use of such methods is supported by a

growing body of experimental and theoretical research. Geoscience search techniques

can complement traditional methodologies in the search for buried objects, including

clandestine graves, weapons, explosives, drugs, illegal weapons, hazardous waste and

vehicles. This paper details recent advances in search and detection methods

conducted at a macro-scale (kilometres to metres), with case studies and reviews.

Relevant examples are given, together with a generalised workflow for search and

suggested detection technique(s) table. Forensic geoscience techniques are continuing

to rapidly evolve to assist search investigators to detect hitherto difficult to locate

forensic targets.

Keywords: geoscience; forensic; burials; remote sensing; geochemistry; geophysics

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1. Introduction

Pye and Croft (2004) define forensic geoscience as “the application of geoscience and

wider environmental science techniques to investigations that could potentially be

brought before a court of law”. As such, it encompasses a number of sub-disciplines,

such as forensic geology, forensic geophysics, forensic soil science, environmental

forensics, forensic mapping, geomatics and remote sensing. There is also an overlap

with related disciplines, such as forensic archaeology, forensic engineering and

forensic botany (Ruffell and McKinley, 2008), which has driven recent discussions on

defining these varied scientific terms for clarification purposes (Ruffell, 2010).

Various geoscience investigative methods are increasingly being used as a search tool

by law and environmental enforcement agencies, as evidenced by the recent

publication of a number of case studies (Fiedler et al. 2009a; Ruffell et al. 2009a;

Missiaen et al. 2010; Pringle and Jervis, 2010; Novo et al. 2011), research articles

(Dekeirsschieter et al., 2009; Jervis et al. 2009; Arosio, 2010; Hädrich et al., 2010;

Dionne et al. 2011; Schultz and Martin, 2011) and textbooks (Killam, 2004; Pye and

Croft 2004; Pye, 2007; Ruffell and McKinley 2008; Chainey and Ratcliffe, 2008), and

the organisation of several international ‘forensic geoscience’ meetings (e.g. Ritz et

al. 2009). Forensic geoscience is currently considered not only to be an emerging

discipline that can bring significant benefits to policing, but an application of

geoscience methods that can provide important results in environmental,

humanitarian, military and engineering investigations.

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Ruffell and McKinley (2005) reviewed the early history of forensic geoscience and

the main sub-disciplines with relevant case studies. Traditionally, forensic geoscience

methods involved the analysis of soil and materials as trace evidence to determine if

there was an association between a suspect or other object or item and a scene of

crime. The quest for associative evidence was replaced by the legally-robust

exclusionary principle (Chisum and Turvey, 2007; Morgan and Bull, 2007a), an ethos

that has its place in the context of this article and forensic searches, whereby all areas

without a buried target are excluded, leaving only those with possible targets. The

traditional use of soil or sediment analysis was expanded in the 1990s when

geoscience methods started to become applied for forensic searches for buried or

concealed objects, largely because of the widespread use of remotely-sensed data and

increasing ease of use and good quality outputs from shallow geophysical methods.

Since the turn of the millennium, there has been an increased use of forensic

geoscience methods in law enforcement, environmental and humanitarian search

investigations which have correspondingly led to an increased number of published

articles, along with more academic papers on a range of experimental and theoretical

research projects as are detailed in this paper.

Geoscientific methods are being increasingly utilised and reported upon by forensic

search teams for the detection and location of clandestinely buried material. In these

situations, burials are usually shallow (less than 3 m below ground level or bgl). The

forensic objects being searched for vary from illegally buried weapons and

explosives, landmines and improvised explosive devices (IEDs), drugs and weapons

caches to clandestine graves of murder victims and mass genocide graves. In

addition, the disposal of toxic waste in illegal dumps is a significant and growing

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issue (Ruffell and Dawson, 2009). Water-based forensic geoscience surveys have

been undertaken to assist police and environmental divers, especially in water with

poor visibility or large search areas, but these will not be covered in this review.

Parker et al. (2010) provide a comprehensive review of forensic geophysical searches

within freshwater bodies, which includes seismic, side-scan sonar, magnetics and

water penetrating radar (WPR). For marine forensic geophysics searches we would

refer the reader to Missiaen and Feller (2008), Leighton and Evans (2008), Missiaen

et al. (2010) and Reynolds (2011) for case studies.

This review focuses on the use of geoscientific methods for the search for objects or

substances that are concealed in the ground and whose presence there constitutes

some form of civil, criminal or humanitarian crime. For example, objects may be

buried in the ground as part of an attempt by a criminal to evade justice (e.g. the burial

of evidence, such as a the corpse of a murder victim); other objects may be buried as a

form of storage in order to facilitate later crimes (e.g. stashes of weapons or illegal

drugs); or hazardous materials may be disposed of illegally in the subsurface in order

for criminals to avoid the costs of legally disposing of such materials. As a result of

this definition, this review does not cover the substantial aspect of forensic geoscience

that relates to the study of trace evidence that may link offenders to crime scenes; we

would refer the reader to other published material (e.g. Pye and Croft, 2004; Ruffell

and McKinley, 2008; Morgan et al. 2008; Morgan et al. 2010) or reviews (e.g. Ruffell

and McKinley, 2005; Morgan and Bull, 2007b). This review focuses on articles

predominantly published within the last ten years due to the rapid expansion of this

area. The review paper structure progresses through an idealised search workflow,

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from remote sensing and desk-based studies to site reconnaissance, and ends at

intrusive investigations.

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2. Overview of current police and environmental search practices

2.1 Criminal law enforcement context

There are four core functions that can describe all law enforcement activity, namely

investigation, interview, search and recovery (Harrison and Donnelly, 2009; Larson et

al. 2011). Without locating the evidence (e.g. a victim’s body), obtaining a successful

conviction can be very difficult. A UK law enforcement definition of search is “the

application and management of systematic procedures and appropriate detection

equipment to locate specific targets” (Harrison and Donnelly, 2009). Traditional law

enforcement search methods have involved large-scale searches of areas with

personnel ‘finger-tip/line searches’ and often conducting trial-and error excavations of

suspect areas. These methods are still used and can prove very effective; however,

law enforcement planning searches now have many more methods to assist their

work.

Currently in the UK, a search strategist is involved at an early stage during a case

investigation for target detection. They will decide upon ‘the most cost effective way

to achieve the minimum standard (resolution) required for a high probability of search

success’ (p.201, Harrison and Donnelly, 2009). In other countries a search may not

be as methodical, investigations may not be standardised and a variety of techniques,

experts and scientific rigour are undertaken, depending upon local experience (see

Larson et al. 2011). Usually forensic search investigators will use a host of proven

methods for detecting targets, which can include scenario-based, feature focused,

intelligence-led and lastly systematic Standard Operating Procedures (SOPs).

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Scenario-based will use available case intelligence and psychological profiling.

Feature focused will identify physical landmarks that may have been used by the

offender to relocate a burial site. Intelligence-led will be based on available case

information (including covert surveillance) and lastly SOPs will provide a proven

search strategy. These aspects are discussed in more detail by Harrison and Donnelly

(2009) and Larson et al. (2011) with law enforcement investigation processes

comprehensively described by Walton (2006) and Geberth (2006).

2.2 Environmental law enforcement context

The illegal burial of waste is becoming an increasing problem globally as costs of

legitimate disposal and recycling have dramatically increased. For this reason,

various geoscience methods have been used in the detection of buried waste and later

prosecution of suspects. Ruffell and Dawson (2009) document various environmental

forensic investigations of illegal waste in Northern Ireland. Illegal disposal of waste

has to ‘be detected and characterized, before a criminal charge can be brought against

the perpetrators’ as Ruffell and Kulessa (2009) state. Ruffell and Kulessa (2009)

detail the successful searches and characterization of illegally buried foot-and-mouth

animal mass graves and illegal conductive and non-conductive waste deposits. Suggs

et al. (2002) provide comprehensive guidelines and resources for conducting

environmental crime investigations in the US. The discovery and determination of the

type and properties of illegal waste can be undertaken by search practices covered

later in this review. Determining exactly when an illegal burial occurred, which has

implications for both the present and past landowners on whose land materials have

been buried, is still currently very difficult (Ruffell and Dawson, 2009). Morrison

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(2000) provides a useful overview of environmental forensic techniques and their

possible applications for age dating and source identification for environmental

litigation purposes.

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3. Identification of the search area(s)

Before detailed physical investigations commence, it is first necessary to identify the

limits of the search area or areas. This may be undertaken by conducting a ‘desktop

study’, combined with a reconnaissance site visit to the search area(s). Usually a site

visit should involve the forensic geoscientist, the civil, criminal or environmental

investigator depending upon the search type and potentially a behavioural profiler if

applicable. A common misconception by non-geoscientists is that there exists one

piece of geoscientific equipment that is successful in all search environments for all

target types. In our view this mistake can be costly – beginning a search with no prior

knowledge of the target size, shape or makeup, or of the local geology, soils and

history of the site will inevitably mean that the wrong equipment and approach is

adopted and the search will be compromised. There are a variety of geoscientific

methods that can be utilised to provide critical background information to implement

a satisfactory search strategy. These are now briefly reviewed.

3.1 Remote sensing

Brilis et al. (2000a,b) and Grip et al. (2000) provided a comprehensive overview of

remote sensing methods in forensic investigations, which includes aerial photography,

topographic mapping, satellite imagery and global positioning systems (GPS)

applications. Brilis (2000a) details the usefulness of early forensic balloon unbiased

photographs, taken just after the 1906 San Francisco earthquake, to detail the location

and extent of damage caused both by the earthquake itself and by non-earthquake

insurance homeowners setting fire to their own homes.

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Aerial photographs can be used to identify unusual features and/or patches of

vegetation (France et al. 1992; 1997; Hunter and Cox, 2005), especially when taken

when the sun is at a low angle, which can accentuate more subtle features (France et

al. 1992; 1997; Hunter and Cox, 2005). Historical photographs are also a useful

resource when they can be compared to recently acquired imagery to determine both

potential locations of burials and the time when the burial had taken place (Ruffell

and McKinley, 2008). Other forensic-relevant features may also be identified, e.g.

sediment plumes caused by the dumping of a body and associated objects in a lake

(Ruffell and McKinley, 2008) and to identify access points from roads to a suspect

location (e.g. Ruffell and McKinley, 2008). Access points are prime search locations

as heavy objects are rarely carried more than 150 metres before being buried (Killam,

2004). The time of day and year when the photograph was taken is obviously key for

some searches and in certain environments (for instance in woodlands), the technique

may not be that helpful due to vegetation cover. Brilis et al. (2000b) detail an

environmental forensics case study, using photographs to detail the damage and extent

of environmental damage caused by lead-zinc mining in Missouri, USA, which, when

combined with historical lease and ownership information, determined the cleanup

liability by respective site-owning companies. Abbott (2005) used historical

photographs to show that a mining fraud case defendant could not have improved a

road as it was eroded before it was alleged to have been used. Ruffell and McKinley

(2008) detail the use of photographs in three case studies of discovering and

monitoring environmental pollution in Northern Ireland.

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Ultraviolet (UV) photography is increasingly being used in forensic investigations to

map the maturity of vegetation - on the premise that any vegetation growing over

recently buried material will be younger than the surrounding plants (Ruffell and

McKinley, 2008). Localised vegetation growing over a burial may also have different

characteristics to background areas; containing different species and with more or

stunted growth for example (Dupras, 2006; Killam, 2004) that Larson et al. (2011)

attributes to both localised pH changes. Ruffell and McKinley (2008) document a

case study in Northern Ireland where illegal toxic waste positions were identified

using infra-red imagery (IR), even when the perpetrators were aware of this method

and had tried to hide the heat emission from these deposits by covering them with peat

and soil. IR and UV photography are also often undertaken to non-intrusively

examine scenes of crime, e.g. to detect ground disturbance and to determine tyre

travel positions before physical examination of the scene commences (Ruffell and

McKinley, 2005). Satellite imagery datasets are many and varied; hyperspectral

imagery, for example, has proven useful to determine locations of individual

clandestine graves and mass graves in areas of rapid vegetation growth, changing

land-use and humid climates in Colombia (Ruffell and McKinley, 2008; Equitas,

2010). Silvestri et al. (2008) document how remote sensing identified illegal buried

waste on an Italian flood plain using remote sensing methods. Light Detection And

Ranging (LiDAR) airborne data capture systems can be used to very rapidly collect

laser scan three-dimensional points in most weather conditions. This has a significant

advantage over aerial or ground photographs (Ruffell and McKinley 2008). Suspect

burial areas can also be rapidly scanned to create a high resolution digital elevation

model and later interrogated, with no need for photographic rectification. This

technique is routinely used by footwear tread analysts to collect scene data (Geradts

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and Kelizer, 1996; Bennett et al. 2009). Thermal imaging equipment may be aircraft

mounted (e.g. Dickinson, 1976), vehicle mounted or hand-held (Davenport, 2001;

Statheropoulos et al. 2011). Hand-held devices have been used for landmine

detection, and objects can be detected even if temperature differences between the

target and background levels are less than 1° C (Deans et al. 2006). Rotary and fixed

wing unmanned air vehicles (UAV’s) are now becoming mainstream with UK and

international Police Service personnel enabling “real time” remote sensing to be

conducted over a search area with the added ability of being flown in a covert manner.

For both clandestine burials (e.g. Dickinson, 1976) and illegal waste deposits (e.g.

Ruffell and McKinley, 2008), the optimum time to conduct a thermal imaging survey

is just before sunrise or just after sunset, and this is thought to be due to localised

increases in temperatures and different rates of heat gains/losses of disturbed soil

compared to the surrounding environment (Davenport, 2001; Larson et al. 2011).

Clandestine graves are thought to be most easily detected with thermal techniques

during the first few weeks of burial (Dickinson, 1976, found buried animal was

detectable for up to 17 days post-burial), although this time frame will be influenced

by the local geology, ground water level and soil type(s); after this time, it gets

progressively more difficult to pinpoint burial locations using this technique (Larson

et al. 2011). Silvestri et al. (2008) document how a combination of thermal imaging

and recognition of stressed plant communities identified illegal waste deposit

locations in a floodplain environment. Although a survey area can be covered rapidly,

thermal imaging can be adversely affected by environmental factors such as poor

weather conditions, for example, high rainfall and elevated humidity (Dickinson,

1976).

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3.2 Geomorphology

Geomorphological mapping has been developed in a forensic context through the use

of a combination of topographic and hydrological maps to sub-divide and prioritise

potential search sub-area(s). This technique has proven useful for locating clandestine

graves of murder victims. Ruffell and McKinley (2008) detail a missing person

search in Northern Ireland in which the search area was divided into ten different sub-

areas, based on a landform mapping approach, visibility from roads and paths, etc.

Chainey and Ratcliffe (2008) provide a useful review of GIS and crime mapping, with

case studies using map information to aid forensic investigations, often coupled with

mobile telephone record locations. Historical maps may provide useful information

for assessing what could be present on a site prior to a search. For example, areas that

now have buildings may have been agricultural land and visa versa. Brownfield

(disused urban land) sites can prove particularly challenging with numerous buried

objects. Similarly, records of land use, held in Public Records offices or with local

history societies can be used. Ruffell et al. (2009) document how historical maps and

photographs were used to identify the search area of 19th Century pauper graves in

Northern Ireland.

3.3 Geology and soil mapping

Knowledge of the local geology and soil types can be critical in forensic

investigations. Williams and Aitkenhead (1991) discuss how the lack of knowledge

of the local geology and the poor understanding of the overlying landfill geochemistry

in Loscoe, Derbyshire (UK) culminated in a methane gas explosion and subsequent

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destruction of a domestic house in 1986 seriously injuring three occupants. Lee

(2004) also described a house explosion in 2004, where on investigation it was found

that rather than a local gas leak or malicious damage, methane from underlying coal

seams were the cause of the explosion. Geology can determine where objects can and

cannot be buried and should, therefore, be considered prior to forensic searches (see

Section 4.4). In some cases geological and soil trace evidence may be available and

can help, to identify potential search areas and also, potentially as significantly, to

exclude areas (Fitzpatrick et al. 2009). As such available geological trace evidence

can aid an intelligence led search. Over the last decade national and regional ground

and remotely sensed surveys have generated large-scale spatial digital databases and

maps of solid and superficial geology, soil properties and soil geochemistry. These

have been used for a range of applications including geological and soil resource and

baseline quality mapping, economic prospecting, environmental studies as well as

prediction of the soil provenance for forensic purposes. As well as global soil

information databases (e.g. Harmonized World Soil Database v.1.0, European Digital

Archive of Soil Maps (EuDASM) which covers the different continents, the UN Food

and Agriculture Organizations (FAO) and the European Soil Database (ESDB)), many

countries also have their own higher resolution databases for geology and soils (e.g.

British Geological Survey (BGS) geochemical survey (G-BASE), The Geological

Survey of Northern Ireland (GSNI) Tellus Survey, the United States Department of

Agriculture SSURGO database, the Australian Soil Resources Information System

(ASRIS) and New Zealand National Soils Database (NSD)). These databases are

used most effectively when combined with geological or soil expertise in assessing

aspects of the landscape such as whether soft ground occurs such that burial is

possible (Ruffell and McKinley, 2008).

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Geological mapping combined with expert knowledge was used by Ruffell and

Dawson (2009) in an environmental forensic case of illegal waste movement and

burial in N. Ireland. Trace evidence of bauxites and laterites associated with a small

geological outcrop indicated the location of an illegal dump. The use of soil databases

for forensic applications has been questioned because of the lack of comparability of

forensic specimens (in terms of sample support and quantity of material) with those

collected for generating databases (e.g. Rawlins et al. 2006; Lark and Rawlins 2008;

Pye and Blott 2009), but discussion of this as trace evidence is beyond the scope of

this paper.

3.4 Metal detectors

Metal detector search teams are used during either initial search investigations or as

part of a phased programme, for example, when looking for shallow (i.e. <0.5 m bgl)

buried metallic material in appropriate environments, confirmed by control studies

(Davenport, 2001; Rezos et al. 2010). Example clandestine burial search case studies

using metal detectors are also detailed in Nobes (2000) and Pringle and Jervis (2010).

There are also magnetic object detection devices that can be used in water as well as

diver-operated submersible metal detectors.

3.5 Search dogs

Specially trained search (sometimes referred to as detector) dogs are also used during

either initial search investigations or as part of a phased programme and can be used

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to identify a variety of different buried objects, commonly IEDs (Curran et al. 2010),

drugs, contraband and human remains. Specialist search dogs looking for human

remains are sometimes referred to as cadaver dogs (see Rebmann et al. 2000). Field

trials conducted by Lasseter et al. (2003) showed relatively low success rates for the

cadaver dogs searching for buried human remains (20-40%) compared to 55-95%

success rates for surface human remains (Komar, 1999). Dupras (2006) provides a

good summary of the principles and limitations of using cadaver dogs to locate

clandestine burials of human remains. Other authors have shown that probing the

surface (sometimes referred to as venting) can release gases which dogs can then

scent and thus increase their success rate (Hunter and Cox 2005; Dupras, 2006),

although this may be slow and could potentially destroy forensic evidence. Optimal

environmental conditions for specialist detector dogs to operate in a suspect area have

been found to be air temperatures of 4º C – 16º C, at least 20% humidity, a wind

speed of at least 8 km h-1 and moist ground (France et al. 1992; 1997; Larson et al.

2011). There is also emerging case work experience that barometric pressure can

have a significant effect on the ability of detector dogs to locate sub surface human

remains.

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4. Reconnaissance

4.1 Assessing the search area(s)

A reconnaissance visit to the search area(s) should include an assessment of any

features and obstacles that may influence the choice of areas to be searched, the

potential search methods that could be utilised and their importance (Killam, 2004;

Harrison and Donnelly, 2009). For example, a relatively small search area surrounded

by metal fences may mask any targets resolved by a ground conductivity survey.

Experienced field geomorphologists and intrusive probers, forensic botanists, search

investigators, profilers and soil analysis experts can be involved at this stage (see

Sections 3 and 5 for details). Analysis of the main soil types within the search area is

important as some types may preclude certain search methods to be utilised, for

example (see Discussion), and the importance of characterising the search area soil for

archaeology is shown by Walkington (2010).

4.2 Conceptual geological model, Diggability and RAG maps

Search models for mineral exploration were adapted for forensic purposes during the

1990s for clandestine grave searches of the Pennines in the UK (see Harrison and

Donnelly, 2009). These conceptual geological models (CGMs) provide information

of the expected target(s) size, age, geometry, depth and surrounding ground

conditions. Time since burial will be important in the search for human remains as

optimum detection technique(s) may vary (see Pringle et al. 2012a). Ground

conditions include the local geology, geomorphological, geophysical, geotechnical

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and hydro-geological regimes (see Harrison and Donnelly, 2009). CGMs should

facilitate and partly pre-determine the optimum choice(s) of the investigative search

technique(s). Obviously as the investigation progresses and new information is

gathered, the initial model will need continual refining. Figure 1 is shown as a

generalised example, although see Harrison and Donnelly (2009) and Killam (2004)

for detail. Related to the CGM is a diggability survey, a qualitative assessment of the

ease by which soils and superficial deposits may be excavated and reinstated. This

can provide information on the difficulty of excavation (which may rule out an area),

the achievable burial depth and time taken to undertake such an exercise. It can also

provide information on the local subsurface, aid the identification of any resulting

features remaining after burial and refine the initial conceptual burial model. This

approach has been used in other forensic areas, for example, in environmental

forensic investigations after a mass disaster such as the Hurricane Katrina devastation

in New Orleans, US, where geotechnical assessment of the catastrophic canal bank

collapse was undertaken to determine the likely causes (Seed et al. 2008).

Once the preliminary CGM and diggability surveys are completed, a simple RAG

(Red-Amber-Green) prioritisation map of the survey area(s) should then be developed

to help focus and prioritise search resources.

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5. Phased site investigations

Once the identified search area and site reconnaissance stages have been completed,

the forensic search investigator(s) will normally then review available case and site

data and decide upon the optimum search technique(s). These technique(s) will be

case and survey site specific (see Discussion) and may well be a combination of

techniques – with perhaps an early survey phase rapidly covering the survey area and

identifying anomalous areas before a further phase of surveys are undertaken focused

on the identified anomalous areas. For example, Nobes (2000) undertook a bulk

ground conductivity survey within woodland before later Ground Penetrating Radar

(GPR) surveys over the conductivity identified anomalous areas led to success at

identifying a clandestine grave position. There are an ever-expanding number of

search techniques that could be utilised as Ruffell and McKinley (2008) document

and some that have already been discussed in the site reconnaissance section. Other

forensic search techniques will now be reviewed; near-surface geophysics in a law

enforcement, environmental and humanitarian context is referred to here as the top 10

m bgl as the maximum depth of search although more usually it is the top 1 m bgl

(Fenning and Donnelly, 2004).

5.1 Seismology

On a large scale, seismology has been used in the investigation of international

incidents involving explosions and impacts, as the energy released can be detected by

seismic networks. Examples of forensic seismology include the investigations of the

Kursk submarine disaster (Koper et al., 2001), the Lockerbie (Scotland) aeroplane

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crash (Redmayne and Turbitt, 1990), the Oklahoma City (US) bombing (Holzer et al.,

1996) and the Nairobi US Embassy bombing (Koper et al. 2001; Koper, 2003).

Seismology could also potentially be useful for investigating covert underground tests

of nuclear weapons (Douglas et al., 1999). Seismo-acoustic methods are showing

promise to detect Improvised Explosive Devices (IEDs), mine and Un-eXploded

Ordnance (UXO) locations (see Xiang and Sabatier, 2003; Donskoy et al. 2005; Sutin

et al. 2009). These methods utilise differences between the elastic, acoustic and

reflective properties of buried objects and the surrounding soil (see Reynolds, 2011

for background). A major advantage of this technique is that it works well for non-

magnetic material, e.g. for detection of plastic mines, and can discriminate mines

from smaller, metallic non-target material. However, the data can take a relatively

long time to analyse compared to other techniques, and it is currently difficult to

detect deeply buried material (see Sutin et al. 2009). Hildebrand et al. (2002)

documented that high resolution seismic reflection surveys were effective in locating

a dead pig in a wooden coffin at 2 m bgl in an unmarked grave, if closely-spaced

geophones were utilised. However, they also note that GPR surveys were as effective

in detecting the graves and could be completed much faster. Multi-channel analysis

of surface waves (MASW) is showing forensic potential; for example, Tallavó et al.

(2009) detail how this method could detect 2 m bgl buried wooden trestles that

supported Canadian railway embankments. A micro-seismic approach has been

shown by Arosio (2010) to have the potential to be used to locate earthquake

survivors trapped under rubble if sensors are placed around the site and cross-

correlating seismic sources are used. Reynolds (2011) gives a good overview of both

seismic reflection and refraction surveys, and provides some examples of their use in

a forensic context, such as in environmental forensic searches to characterise landfill

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sites or locate buried toxic waste material. Case studies of seismic methods used to

characterise contaminated land sites and illegally buried solid waste are given by

Cardarelli and Di Filippo (2006) and Grandjean (2006) respectively. Reynolds (2002)

detailed an environmental forensic survey of a polluted pond in North Wales, UK,

where a seismic reflection survey was utilised to characterise the thickness of toxic tar

waste at the bottom of the pond.

5.2 Bulk ground conductivity

There has been limited use of Electromagnetic (EM) surveys for law enforcement

investigations, which is surprising considering its relatively rapid survey rate and

ability to be carried through woodland environments, where other techniques may not

be useful. Frohlich and Lancaster (1986) deployed a Geonics™ EM-31 instrument in

Jordan to locate and characterise unmarked burials and tombs, with resulting target(s)

contrasts with background levels dependent on the proportion of silt present within

the graves. Nobes (2000) documented the successful search for buried human

remains in a wood, initially by utilising an EM survey to identify anomalous areas,

with follow-up GPR investigations over these suspected burial areas. Nobes (2000)

also suggested that the victim’s clothing may have trapped decompositional fluids

during dry conditions (see section 5.3) which were detected by EM methods. France

et al. (1992) also found EM surveys could successfully locate simulated clandestine

burials of pig cadavers in the Western US. Larson et al. (2011) suggested low-energy

EM fields could be detected from burials as bone is piezoelectric. Witten et al. (2001)

also conducted an initial EM survey to look for mass graves in Tulsa, USA, before

follow-up magnetic and GPR investigations were undertaken. Pringle et al. (2008)

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conducted a controlled experiment in a UK urban garden environment and found that

a Geonics™ EM-38 instrument, which is designed to be placed on the ground and

therefore should be less susceptible to above-ground interference, did not resolve the

target ‘grave’. This was attributed to the local urban environment and ‘made ground’

nature of the burial site. Nobes (1999) also found difficulty using EM methods to

locate unmarked graves in a cemetery in New Zealand, due to differentiating

anomalies from significant background effects caused by fence boundaries and local

topography. Interestingly Nobes (1999) found that the ‘head’ ends of unmarked

graves were easier to identify than the ‘foot’ ends.

Saey et al. (2011) have shown a combined EM induction sensor approach can be used

to detect UXOs in former WWI battlefields in Belgium. High resolution time-domain

EM surveys have also shown promise for UXO detection (Pasion et al. 2007).

Researchers have also used EM methods to detect landmines (Combrinck, 2001) and

buried weapons in a controlled environment (Dionne et al. 2011), although equipment

resolution and background variations in soil type can make the detection of small

targets problematic. EM survey equipment needs to be carefully calibrated to the

local site conditions and can also be significantly affected by above-ground

conductive objects, e.g. metal fences, electricity pylons, cars, etc., which may

preclude their use in certain search areas and environments, such as urban areas (see

Reynolds, 2011; Milsom and Eriksen, 2011). Electromagnetic (EM) surveys can be

used for environmental forensic geophysical surveys (see Reynolds, 2011), as the

target is usually more conductive than background site materials. Bavusi et al. (2006)

detail a case study in which an EM survey was used to characterise a waste dump in

Southern Italy. Vaudelet et al. (2011) shows an urban contaminant case study

23

characterising different source sites. As conductivity surveys using conventional

instruments (such as the Geonics™ EM31 or EM38 [Geonics Ltd., Mississauga,

Canada]) are directional, they can focus on either the top 5-8 m bgl (using the

horizontal model component or HMD) or up to 15 m bgl (using the vertical mode

component data or VMD), depending upon the suggested depth of burial bgl and the

local site ground conditions.

5.3 Electrical methods (resistivity)

Resistivity is the reciprocal of conductivity, with resistivity surveys actively

measuring the bulk ground resistivity of a volume of material below the sample

position (see Reynolds, 2011 and Milsom and Eriksen, 2011 for background and

operation). Typically, fixed-offset resistivity surveys are utilised for searches, due to

their relatively rapid coverage of the ground, although Electrical Resistivity

Tomography (ERT) 2D profiles have also been collected over simulated clandestine

burials (Pringle et al. 2008) and illegal waste dump sites (Ruffell and Kulessa, 2009)

which also gives depth information. Basic 2D resistivity modelling can also be

undertaken to gain a better understanding of resistivity survey results (see Scott and

Hunter, 2004). Resistivity surveys have the advantage of being less affected by

above-ground material (i.e. background ‘noise’) when compared to EM surveys as

probes are shallowly placed into the ground surface. They also work well in clay-rich

soil types (see Pringle and Jervis, 2010). However, resistivity survey results can be

problematic if undertaken after metal detector search teams have searched for buried

items due to disturbances and small voids as detailed by Pringle and Jervis (2010).

24

Resistivity has been successfully used to locate unmarked burials in cemeteries (e.g.

Buck, 2003) and ancient tombs (e.g. Persson and Olofsson, 2004; Powell, 2004;

Matias et al. 2006) although local variations in soil moisture content, particularly in

heterogeneous ground in relatively dry conditions, can affect survey success by

masking target location(s) (Ellwood et al. 1994) and/or result in numerous non-target

anomalies being imaged (see Pringle et al. 2012a). Resistivity datasets can also be

highly affected by coarse-grained and larger (e.g. cobble) soil types, as well as saline

conditions (e.g. Pringle et al. 2012b). Milsom and Eriksen (2011), however, point out

that obtaining data from the area surrounding graves can be problematic due to the

inability for probes to penetrate concrete, tarmac or other hard surface. Resistivity

surveys have been successful in locating clandestine graves; for example Ellwood et

al. (1994) imaged three anomalies when searching for the hanged Texan gunfighter

William Preston Longley. Scott and Hunter (2004) and Pringle and Jervis (2010) both

detail the use of resistivity surveys in rural Welsh fields in their respective

unsuccessful missing person searches. Pringle and Jervis (2010) used semi-

quantitative analysis of resistivity data to identify anomaly locations, and compared

the results to simulated study results. Published control studies over simulated burials

(e.g. Cheetham, 2005; Jervis et al. 2009) have therefore proved useful for forensic

investigators for comparison with active search data; these studies typically used a

small grid survey pattern (0.25- to 0.5-m-spaced data point samples) so that targets

could be resolved. Low resistivity anomalies with respect to background values

would be expected to occur over clandestine burials of murder victims, due to

increased soil porosity (Scott and Hunter, 2004) and the presence of highly conductive

decomposition fluids (see Jervis et al. 2009; Pringle et al. 2010). However, Jervis et

al. (2009) found that high resistivity anomalies, with respect to background values,

25

were observed over clandestine burials with a wrapped pig cadaver, and concluded

that the wrapping prevented decomposition fluids being released into the ground and

the wrapped cadaver presented a barrier to electrical currents. This temporal study

has been continued and found resistivity anomalies to be present at least three years

post-burial (see Figure 2 and Pringle et al. 2012a). Decompositional fluid

conductivity has been documented to change markedly over time since burial, rapidly

increasing in year one and slowly increasing in year two, before decreasing by the end

of year three post-burial (see Pringle et al. 2010). These variations will undoubtedly

be different in different soil types and in different regions and environments in the

world. Juerges et al. (2010) documented that decompositional fluid may be detectable

below surface pig remains, even when no physical evidence of the cadaver remained.

Resistivity methods (particularly ERT) are a standard investigatory tool for

environmental forensic investigations. Environmental applications of the technique

include looking for leachate leaking from landfills (see Reynolds, 2011) and

contaminant plumes from urban sites (see Vaudelet et al. 2011), identifying where

illegally buried solid waste may be located (Cardarelli and Di Filippo, 2004; Ruffell

and Kulessa, 2009) and studying potential aquifer contamination by graveyards

(Matias et al. 2006). Ruffell and Kulessa (2009) also document a Northern Ireland

case study where a combination of ERT and GPR surveys were used to locate animal

mass graves from the 2001 foot-and-mouth cattle epidemic.

5.4 Ground penetrating radar (GPR)

26

Ground penetrating radar (or GPR) is a commonly used near-surface geophysical

technique for the detection of unmarked grave locations, clandestine graves and

various other buried materials, with radar reflections caused by contrasts in dielectric

permittivity (Figure 4). Successive 1D radar traces are collected to build up vertical

2D profiles of the sub-surface, with 3D datasets being collected if time permits (see

Jol, 2009 for background theory and operational detail). Commonly bi-static, fixed-

offset transmitter-receiver antennae with fixed frequencies are used to acquire a series

of 2D profiles. GPR has arguably one of the highest resolutions of near-surface

geophysical survey techniques and data can be obtained relatively quickly, depending

upon the equipment, antennae frequency and trace sampling spacing utilised. It is one

of the most commonly used techniques for near-surface target detection and widely

used in the geotechnical industry for buried utilities (see, for example, Metje et al.

2007). GPR has also been shown to work successfully to locate snow avalanche

survivors (see Instanes et al. 2004). However the method does not work well in saline

environments due to poor penetration (see Pringle et al. 2012b). There have also

been studies showing reduced penetration in damp clay-rich soils although if this is

homogenous it is not a big problem (see Nobes, 1999); more of an issue is

heterogeneous ground as is discussed later in this paper.

There are a number of published papers that describe the use of GPR in cemeteries to

locate unmarked graves (e.g. Kenyon, 1977; Ellwood, 1990; Bevan, 1991; King et al.

1993; Nobes, 1999; Davis et al. 2000; Watters and Hunter, 2004; Powell, 2004;

Fiedler et al. 2009a) and searching for a clandestine grave in a cemetery (Ruffell,

2005b). Conyers (2006) suggests GPR can detect the disturbed grave back-fill, the

coffin itself, its contents and any grave ‘fluid’, although Nobes (1999) highlights that

27

age of burial is important with associated variability in burial styles and

decomposition causing target detection and signature to very considerably, even

within the same burial site. Historical graves can often be difficult (though not

impossible) to detect due to the limited skeletal remains and the process of soil

compaction (e.g. Vaughan, 1986). Published clandestine grave searches using GPR

include Mellet (1992), Calkin et al. (1995), Davenport (2001) and Billinger (2009).

Nobes (2000) detailed a GPR survey which followed up on anomalous areas

identified in an EM survey looking for a clandestine grave in woodland. Novo et al.

(2011) also detail a difficult GPR search for a grave in a mountainous area. The use

of legal cemetery graves as a proxy for covert burials is dubious due to the different

burial depths (typically 2 m bgl for graves and 0.5 m bgl for clandestine graves).

However, some rapid legal burials may provide suitable approximations for

clandestine graves. For example, Davis et al. (2000) document a GPR survey for

unmarked and shallowly buried, Spanish Influenza victims from 1918 in Svalbard,

Norway. Ruffell et al. (2009a) showed a GPR case study of mass graves from the

Irish ‘Potato Famine’ in the 19th Century. Ruffell and McKinley (2008) also point out

that the additional material in legal graves (coffin, clothes, lime, disinfectant,

embalming fluid, etc.) that may prevent results from being comparable to clandestine

burials.

Controlled grave studies, whereby animal remains (typically pig cadavers) are used as

a proxy for human remains, have been used to determine whether GPR could be

successful to locating a target. An early example of this was that of France et al.

(1992) a multi-disciplinary study in the USA. Strongman (1992) also published a

series of case studies, using 5 year old bear carcasses with comparison to case results.

28

Miller (1996) also documents control studies and shows how historical graves can be

utilised as comparisons. More recent control study examples include sequential GPR

monitoring over large (Schultz et al. 2006) and small (Schultz 2008) pig cadavers and

a simulated clandestine grave with accompanying GPR time-slices (Pringle et al.

2008). There are currently differing views amongst researchers on which set

frequency GPR antennae should be utilised for forensic searches. GPR antennae

commonly range from 50 MHz to 2000 MHz; Ruffell et al. (2009a) suggest 200 MHz

was optimal to detect shallow buried unmarked historical graves, and used 400MHz to

image an individual burial, and Schultz and Martin (2011) showed both 250 and 500

MHz antennae could be utilised to detect simulated clandestine graves, whilst others

suggest higher frequencies (e.g. Buck, 2003 used 800 MHz frequency GPR antennae

to locate unmarked graves). The general consensus seems to be that optimum

detection frequency will depend on target size, depth bgl, geology and soil type.

Ruffell (2005b) gives a good review of some of these parameters, showing sandy soils

are optimum for GPR surveys; this was also supported by France et al. (1992);

although note surveys will always be site specific and depend upon depositional

processes. For example, Nobes (2007) detailed five burial sites in New Zealand with

different soil types and found sandy soil did not show targets, as depositional

processes mimicked grave responses, whereas the homogenous clay-rich soils could

be processed to resolve graves. High clay content soils and saline conditions (Pringle

et al. 2012b) also significantly reduce radar penetration depths. A current major

limitation is the speed of data collection that precludes whole fields to be surveyed,

and the significant post-field data processing time to optimise datasets. There has also

been research to numerically model the expected GPR responses from buried human

remains in different soil types (Hammon et al. 2000). Cassidy (2007a) reviews GPR

29

numerical modelling methods for a variety of buried targets. Millington et al. (2011)

go further and invert synthetic GPR data from a simulated clandestine grave for

automatic target location purposes although this is currently still being developed.

Solla et al. (in press) used a different approach using finite-difference time-domain

(FDTD) modelling of GPR data acquired over simulated buried forensic objects and

used ground-based photogrammetric methods to calibrate the modelling.

Acheroy (2007) reviewed both remote and field detection of anti-personnel mines

using GPR methods, EM sensors and remote sensing. He also documented the main

current police and military search forensic geophysical detection equipment which are

a combination of GPR and metal detectors, with Bruschini et al. (1998) showing a

case study of these combined methods. Lopera et al. (2007) showed how numerical

filtering of GPR signals can reduce non-target cluttering of GPR datasets when

looking for shallow buried landmines, using an example from Colombia. Lopera and

Milisavljević (2007) documented how important the knowledge of soil type is to

predict the GPR responses from metallic and non-metallic landmines. Furthermore

Sato et al. (2004) provided information on the potential for using GPR antennae

arrays to obtain common mid-point (CMP) multi-fold datasets for landmine detection,

a significant improvement than the typical fixed-offset 2D profiles commonly

acquired. For environmental forensic target detection, there are case studies given in

Reynolds (2011), ranging from mapping of contaminated land, pinpointing of illegally

buried, toxic waste (see Orlando and Marchesi, 2001; Ruffell and Kulessa, 2009) to

mapping groundwater contamination from landfills (Davis and Annan, 1989),

chemical (Brewster and Annan, 1994) and hydrocarbon spills (Cassidy, 2007b;

Bermejo et al. 2007). These can often be observed by radar signal attenuation and

30

dielectric permittivity contrasts, although note geophysical detection can be

temporally variable depending upon contaminant size, concentration and dispersal

rates (see Greenhouse et al. 1993; Sauck et al. 1998).

5.5 Magnetometry

Highly sensitive magnetometers have had varied success in forensic applications.

Ancient archaeological graves have been shown to have high magnetic susceptibility

(Linford, 2004), proposed as due to being long term mineral changes caused by

bacterial action. However magnetic results over simulated recent clandestine burials

in a variety of depositional environments have proved to be not that useful (see

Juerges et al. 2010). Ellwood (1994) and Witten et al. (2000) encountered difficulties

in locating 19th Century graves in cemeteries and a mass grave from 1921,

respectively, using magnetic methods. Magnetic susceptibility analysis was

undertaken on illegally dumped soil on a motorway in China that caused multiple

fatalities and successfully identified its origin (Manrong et al. 2009). Pringle et al.

(2008) pointed out that magnetic susceptibility datasets can also be used for quality

control checking of magnetic gradiometry datasets: e.g. for assisting with the removal

of magnetic data spikes. Recent field trials by the authors have shown magnetic

susceptibility methods are optimum to detect buried metallic targets beneath a

domestic patio (Figure 4) versus total field and gradient methods (see Reynolds, 2011

for background). Magnetic surveys collected by helicopters flying at a low altitude

have also proved useful in identifying UXOs; Billings and Wright (2010) provide a

good example from a former army range in Canada. For land-based surveys for UXO

detection, case studies using specialised magnetometers have been published on

31

multi-sensor 3-axis magnetometers (Munschy et al. 2007), quad-sensor arrays

(Billings and Youmans, 2007) and borehole magnetometry (Zhang et al. 2007).

However, Butler (2003) details the importance of understanding the background

magnetic susceptibility for identifying and locating UXOs and uses case examples

from Indiana and Hawaii, USA. In environmental forensic applications, Marchetti et

al. (2002) detail how magnetic methods identified where over 160 illegally buried

solid metal drums were located, with a recent paper showing how test sites can aid

magnetic data interpretation (Marchetti and Settimi, 2011).

5.6 Forensic geomorphology

A forensic geomorphologist can conduct visual inspections of the ground surface to

assess likely burial positions (see Owsley, 1995). Generally, the lower density of

backfilled soil and the buried target itself may initially result in a raised mound on the

ground surface (Killam, 2004). However, over time some disturbed soil may become

compacted as material density increases, resulting in localised ground depressions.

Ground depressions can become even more pronounced in searches for human

remains when cadaver chest cavities collapse (Rodriguez and Bass, 1985). Other

scientific observations that may indicate the presence of clandestine graves include

unusual localised vegetation changes, including lower species diversity/maturity,

improved/decreased vegetation growth (see France et al. 1992; Killam, 2004; Hunter

and Cox, 2005; Caccianiga et al. 2012), evidence of animal scavenger activity (France

et al. 1992; Turner and Wiltshire, 1999; Hunter and Cox, 2005; Dupras et al. 2006;

Wilson et al. 2007), entomology (see Amendt et al. 2007 for a detailed review) and

human activity, including discarded burial tools (Killam, 2004).

32

5.7 Intrusive probing

Owsley (1995) suggests that suspected burial areas be intrusively probed, allowing the

operator to `feel’ whether disturbed soil or even a buried cadaver is present, although

this may compromise forensic evidence. To quantify this process, suggestions have

used a spring gauge mounted on a probe to obtain quantitative measurements of soil

strength (Ruffell, 2005a) or a penetrometer (Killam, 2004); the resulting data points

can then be gridded, contoured and analysed to pinpoint anomalous areas with low

soil strength with respect to background values. Both methods are essentially using

the concept of ‘diggability’ applied to ground searches (see Section 4.2), in that a

perpetrator cannot bury an object where ground is hard or the soil is too thin. Fiedler

et al. (2008) detailed a successful intrusive probing case study pinpointing World War

Two mass graves in dense woodland in Germany that precluded the use of other

search methods. Note however the potential for damage to buried material and hence

potentially crucial forensic evidence.

5.8 Soil analysis

For the location of human remains, the chemical alteration of surrounding soil can be

detected, with authors suggesting a programme of soil samples from search area(s)

should be analysed to locate anomalous high element concentration regions with

respect to background values (Tibbett and Carter, 2008; Benninger et al. 2008;

Dekeirsschieter et al. 2009), especially for Nitrogen (Carter et al. 2008; Van Belle et

al. 2009) and human-specific carbon (Bull et al. 2009). Decomposition fluids

33

associated with buried animal remains can be detected using resistivity (Jervis et al.

2009), with fluid analysis showing them to be highly conductive when compared to

background soil water values (Pringle et al. 2010). McKinley et al. (2008) detail a ‘no

body’ forensic search case in Western Ireland using chemical analysis as one potential

search tool. Decomposition fluids and Volatile Organic Compounds (VOCs) have

also been shown to vary in elemental concentrations over time (see Juerges et al.,

2010 and Vass et al. 2004; 2008 respectively).

Electronic gas detectors (referred to as methane probes), which are able to analyse gas

drawn through metal probes inserted into the ground, have also shown promise for

grave detection (Killam, 2004; Hädrich et. al, 2010) although results should be used

with caution in case values are due to other emitting sources (e.g. from peat). Buried

sampler modules collecting gases over time have also been suggested as an alternative

detection method (Ruffell, 2002). It has also been suggested that decomposition gases

can be detected by laser spectroscopy (Ruffell, 2002), and GC-MS analysis of human

specific VOCs by headspace sampling methods (see e.g. Hoffman et al. 2009;

Lovestead and Bruno, 2011).

5.9 X-ray techniques

A continuous operating scanning X-ray source for landmine detection using

backscatter X-rays has been developed and it has been proved possible to distinguish

between plastic and metal mines due to relative mass density differences between

targets and background materials (Niemann et al. 2002; Yuk et al. 2006). However,

the equipment is not easily portable, and safety concerns relating to X-ray levels limit

34

the depth to which signals can penetrate in soil. A field portable X-ray fluorescence

spectrometer has been developed; Bergslien et al. (2008) discuss forensic geoscience

search applications, including location of cremated human remains, and identifying

both the environmental polluting source of illegal waste and tracking its movement

through the local environment.

5.10 Nuclear Quadrupole Resonance

Nuclear Quadrupole Resonance (NQR) is a solid state radio frequency technique

which has proven highly effective for the detection of explosives. It works by

inducing a radio frequency pulse into the ground through a coil, which causes the

explosive nuclei to resonate and an electrical potential to be recorded (see Anferova

and Grechishkin, 2005). NQR can distinguish between different forms of the same

compounds, e.g. TNT polymorphs, and has been shown by Somasundaram et al.

(2008) to be relatively unaffected by different soil conditions. However, the

technique has low signal to noise ratios indicating further data processing research is

required to make this technique usable in the field and the technique cannot penetrate

metallic material.

5.11 Radiometrics

Commonly used to locate radioactive rocks for exploration, few environmental

forensic searches using these techniques have been published. Ketterer and

Czechenyi (2008) reviewed atomic analytical analysis techniques, detailing plutonium

surveys at the Nevada atomic test site, USA, the Chernobyl plume in the Ukraine and

35

atomic accidents in Palomares, Spain and Thule in Greenland. Discussion was also

given to using plutonium as a marine tracer, showing it can be traced from the Pacific

Proving Ground to the North Pacific. There are issues with collecting enough data to

be statistically valid and geometric correction factors due to topography variations

(see Milsom and Eriksen, 2011).

36

6. Post-search

Once the fieldwork has been concluded and the data has been processed and

interpreted, a report should be written, detailing the survey’s findings and providing a

prioritised list of area(s) for intrusive investigation, if any (see Harrison and Donnelly,

2009 for more detail). These will obviously be target specific which may vary

considerably, depending on whether the target is a clandestine grave, explosive

material or contaminated land. All data may be questioned in a court of law, so

original and processed information, interpretations, samples, etc must be time and

date stamped and held in a secure, tamper-proof manner. All such items must adhere

to the state rules of chain of custody (see Chisem and Turvey, 2007). The civil,

criminal or environmental investigating officer will then decide on the next

investigative steps. This may or may not involve the geoscientist, depending on

whether further geoscientific investigations are required or not. Follow-up law

enforcement or environment agency options will correspondingly vary, from

excavation and identification of illegally buried material, mine/object clearance,

recovery of human remains or land remediation respectively. For the readers’

information, when a physical excavation is unsuccessful, there is generally an

effective exit strategy in place so that excessive use of manpower and resources is not

used (Harrison and Donnelly, 2009). This does not usually have any input from the

geoscientist so will only be briefly discussed.

6.1 Topsoil removal

37

Topsoil removal is a relatively straightforward method that is appropriate for buried

body searches once the search area has been narrowed down to a relatively small area

or when other search methods have failed (Killam, 2004). This involves the repeated

removal of thin soil surface layers, either until evidence of disturbance is encountered

or a depth is reached such that the area can be ruled out (Hunter and Cox, 2005). This

can be performed using machinery (e.g. Killam, 2004) or by hand-held digging

implements (e.g. Dupras et al., 2006). After enough soil has been removed, disturbed

areas can usually be identified by different coloured soil (see Dupras et al., 2006).

Note however the potential for damage to buried material and hence potentially

crucial forensic evidence. In potential crime scenes it is at this stage of the operation

that the forensic geoscientist will have handed responsibility on to an appropriately

qualified forensic archaeologist (Hunter and Cox, 2005).

6.2 Exploratory trenches and excavations

The final stage of any forensic search is often undertaken by careful trenching and

excavation of prioritised anomalous areas, usually by trenching suspected anomalous

areas pinpointed by the investigations suggested (Hunter et al. 2001; Cheetham, 2005;

Hunter and Cox, 2005). This phase is overseen by the crime scene manager or

environmental investigative officer with trained archaeologists or other relevant

personnel present. A systematic and controlled approach is utilised, for example

when excavating a clandestine grave, this includes detailing the stratigraphy and

relative dating, the grave contents, identifying the burial cut and tool marks whilst

retaining the material relative context. Hunter and Cox (2005) and Dupras (2006)

detail forensic archaeology excavations and best practice methodologies with Skinner

38

(1987) detailing best practice specifically for mass grave recoveries. Hunter and Cox

(2005) also show 29 clandestine burial case studies and mass grave investigations in

former war zones. Walkington (2010) also describes the importance of analysing

suspected areas for forensic archaeology. However, it is important to note that

excavations may not always be successful, with suspect burial areas in fact being due

to something more benign, for example, a test trench for a potential site development

as Ruffell et al. (2009b) document.

39

7. Discussion

Every forensic search of the subsurface will be unique, with different target(s) sizes

(e.g. child to adult clandestine burials), burial depth(s) below ground level (typically

the deeper buried the forensic target, the harder it may be to locate), style(s) of burial

(e.g. for discovered clandestine graves they are commonly wrapped, clothed or

naked), time since burial with its accompanying target variables (see Figure 1),

background soil type(s) (see below), local bedrock (which often affects overlying soil

type(s)), depositional environment (e.g. urban, rural, woodland, moorland, etc.),

vegetation type(s) (e.g. grasses, woods, urban gardens, etc.), local climate (e.g. arid to

humid), water table depth bgl, and many other specific variables. Each of these

target(s) and background site variables will have a limited to very important effect on

optimum search technique(s) and their subsequent target detection success or failure,

so it is very difficult to produce specific guidelines for forensic searches for all

eventualities. However, a generalised table to indicate the potential for search

technique(s) success for relatively common buried forensic target(s) has been

generated in this review (see Table 1). It is important to note that (1) thermal imaging

techniques will be dependent on time since burial (see Section 3.1) and (2) Water

Penetrating Radar survey detection success rates will depend upon target(s) size,

bottom sediment type(s), water depth, salinity and temperature (Parker, pers. comm.).

Side-scan sonar surveys are also dependent on relatively fine-grained sediments

surrounding the target to reduce non-target reflectors (see Dupras, 2006) and water-

based magnetometers would normally only be highly effective in relatively quiet non-

magnetic background sites.

40

Forensic target(s) in Table 1 are deliberately generalised; it would obviously be more

difficult to successfully locate (using magnetic methods) a buried single weapon than

a collection of them. Similarly illegally buried waste would obviously be easier to

detect if it was of significant size and had a high contrast from background materials,

for example buried metallic waste in a rural environment, than relatively small non-

magnetic material in heterogeneous ground. A mass grave may be easier to locate

using remote sensing methods whereas single clandestine graves are much harder to

detect remotely, and very often difficult to detect within a suspect site (see Hunter et

al. 2001).

The generalised search table differentiates between sand and clay site soil type end-

members, although, of course, this is also simplistic as most soils will lie between

these two, normally be heterogeneous and the end members ignore coarser grain-sized

soil types (e.g. river gravels, etc.). Soil type is, however, important to consider for

forensic searches for a variety of reasons. Firstly certain soil types (generally clay-

rich types) result in poor GPR penetration depths, the success rate of element analysis

detection (generally better in sandy soils) and decomposition rates with accompanying

fluid plumes (generally faster and larger respectively in sandy and coarser grain-sized

soils compared to clay-rich types). The search table also tries to judge the influence

of the local search generalised environment, covering the main depositional settings

that include woodland, rural, urban, coastal and underwater environments

(mountainous not included as not a common depositional scenario, although see Novo

et al. 2011). Local burial environment can be important to consider when undertaking

a survey, for example, urban areas will have potential difficulties for search teams to

use some specialist equipment (e.g. conductivity surveys if adjacent to metal

41

fencing/objects) and potentially have many non-target objects buried within the

survey site (see Drahor, 2011). However, environments are also deliberately general

in the table, for example, a GPR survey in woodland with widely-spaced deciduous

trees may be successful (see Nobes, 2000), however, it may be difficult to

differentiate buried forensic targets from tree roots in coniferous woodland with

closely-spaced trees. Exactly where the search site is in the search environment may

also have potentially large variations in potential target detection success, for

example, in coastal environments, technique(s) target detection success may vary

widely depending on whether it is in sand dunes versus the actual foreshore

environment (see Pringle et al. 2012b). Similarly a concrete surface may preclude

certain search technologies (e.g. resistivity) from being utilised due to not being able

to insert probes into the ground; however, GPR methods may be optimal in this urban

environment (see Billinger, 2009).

The generalised table also assumes optimum search technologies are available and

optimum data sampling strategies are chosen for the respective search target(s) within

their specified local environment(s). Small forensic target(s) would normally require

closely-spaced sampling points but this may depend upon target contrast with

background materials and time available onsite. For example, a forensic search to

detect a metallic knife using metal detection equipment in a metal scrap yard would

have a relatively low detection success rate due to their being little contrast between

the target and the background environment. The table also assumes experienced

search operators are undertaking the surveys which also increase the chances of

success as Billings and Youmans (2007) document (86% target location success for

experienced versus 54% for inexperienced magnetic data interpreters); not only would

42

they choose appropriate search detection equipment and sample data spacing, an

experienced forensic GPR team, for example, would undertake soil sampling and trial

2D profiles using all set antennae frequencies to determine the optimum frequency for

a site before a full forensic search survey is initiated. GPR data processors may then

use relatively advanced processing techniques, for example, to remove any above-

ground interference effects (see Pringle et al. 2009) or remove average background

radar responses to reveal target anomalies (see Nobes, 1999).

Combinations of search techniques are considered best practice which would

normally increase the chances of detection success; this is relatively common in

geotechnical (see Sloan et al. 2007) and archaeological investigations (see Arciniega-

Ceballos et al. 2009) for examples. Published forensic examples include multi-

disciplinary searches for the hanged Texan Gunfighter William Preston Longley

(Ellwood et al. 1994), the Nobes (1999) EM and GPR study to locate unmarked

graves and a three year monitoring study of buried pig cadavers showing both GPR

and bulk ground resistivity surveys should be collected if the style of burial (e.g.

wrapped or naked) is unknown (Pringle et al. 2012a). Multi-technique environmental

forensic case studies are provided by Cardarelli and Di Filippo (2004), who used

electrical and seismic methods to characterise illegal landfills, and Boudreault et al.

(2010), who used electrical, magnetic and GPR surveys to characterise a contaminated

urban site.

The timing of the forensic search survey may be important in seasonal climates;

Pringle et al. (2012a) monitoring study showed that winter surveys were statistically

more likely to be successful at target detection rather than surveys undertaken in

43

summer months, concluded due to soil moisture content variations. Combining

techniques also allow the efficient use of time and resources for the best chances of

detection success. A workflow of a forensic search investigation has been generated

that again has been deliberately generalised (Figure 5). Of course the workflow will

need to be altered for each search and refined when further case information becomes

available. A major part of the search effort is undertaken prior to any field

investigations; this has benefits in time, manpower and obviously cost. This review

also strongly recommends that site reconnaissance, including visual inspection, a

diggability survey and perhaps limited trial surveys should be undertaken prior to

more comprehensive site survey work (see Harrison and Donnelly, 2009 and Larson

et al. 2011 for more information). Forensic searches normally do, of course,

encounter problems which Larson et al. (2011) document; whether a case could have

inaccurate or compromised evidence of suspect’s movements, false (positive or

negative) search dog alerts, misreading of soil profiles, misinterpretation of forensic

search datasets, confused evidential records and even investigator bias (see US

National Research Council Report 2009 for more information). It is therefore crucial

to improve search protocols and standardise search methods to ensure scientific

rigour, consistence and highest standards of investigation as Harrison and Donnelly

(2009) and Larson et al. (2011) document.

44

8. Conclusions

From this review it is clear that forensic geoscience methods aid terrestrial searches in

many and varied ways; their applications and recently published case studies are ever

expanding, even since the publication of the Ruffell and McKinley (2005) review;

search methods thus require standardisation and protocols to maximise the chances of

target detection success. Whilst certain countries, such as the UK, are attempting to

standardise methods, other countries globally are just starting to see the potential (see,

for example, Mazari 2010) and applying geoscientific search methods differently and

with subsequent varied success rates as other authors point out (see Larson et al.

2011). Many of the case studies, site investigations and research papers reviewed in

this paper indicate the benefits of multi-disciplinary investigations with integration of

historical and modern information, remote sensing and multiple phases of site work,

to make efficient time savings and to use appropriate equipment and technologies to

focus on search targets. Creating a conceptual target model and continually refining

this when new information becomes available will assist forensic search teams in

developing a detailed and focussed search plan. Key considerations when deciding on

optimum geoscience search techniques and methodologies can be exhaustive and case

specific but should be as a minimum: target type (composition), expected target size,

time since burial, likely depth below present ground level, the local burial

environment, site geology and soil type. Table 1 summarises preferred methodologies

for detection of specific target(s) but, of course, searches will be case and site specific

so this table should not be used as justification for preferred search methodologies to

be utilised on a search case. Clearly there is much empirical and applied research still

to do in order that current search models can be further refined and the capabilities of

45

geoscience methods for ever more effective search operations can be refined. It is

hoped that both researchers and practitioners will continue to evolve in synergy and to

further develop knowledge and research, be quantitative in approach and publish more

research and case study articles to further disseminate current developments.

Acknowledgements

The authors (other than John Jervis, Jamie Hansen and Mark Harrison) are committee

members of the Forensic Geoscience Group, a specialist sub-group of the Geological

Society of London, whose stated mission is to promote the study and understanding of

forensic geoscience nationally and internationally, promoting good practise for

academics and practitioners alike. The International Union of Geological Sciences

(IUGS), Initiative on Forensic Geology (IFG) is also acknowledged for its

contributions to this paper. Mike Ferguson and Sarah Corrigan of the Home Office

Centre for Applied Science and Technology (CAST) are acknowledged for magnetic

and metal detection equipment advice. Emily Giddings is thanked for providing some

burial statistics and Leigh Noble is thanked for UXO/IED detection information.

Three anonymous reviewers have significantly improved the manuscript.

Role of the funding source

The respective author research funders had no involvement in any studies shown,

writing or decisions regarding submitting this paper for publication.

Disclosure Statement

46

There are no actual or potential conflicts of interest by the co-authors.

47

References

Abbott, D.M., 2005. Investigating mining fraud. Geotimes January, 30-32.

Acheroy, M., 2007. Mine action: status of sensor technology for close-in and remote

detection of anti-personnel mines. Near Surface Geophysics 5, 43-56.

Amendt, J., Campobasso, C.P., Gaudry, E, Reiter, C., LeBlanc, H.N., Hall, M.J.R.

2007. Best practice in forensic entomology: standards and guidelines. International

Journal of Legal Medicine 121, 90-104.

Anferova, L.V., Grechishkin, V.S., 2005. Physics of magnetic phenomena—use of the

Bohr principle for detecting NQR signals from mines. Russian Physical Journal 48,

148–155.

Arciniega-Ceballos, A., Hernandez-Quintero, E., Cabral-Cano, E., Morett-Alatorre,

L., Diaz-Molina, O., Soler-Arechalde, A., Chavez-Segura, R., 2009. Shallow

geophysical survey at the archaeological site of San Miguel Tocuila, Basin of Mexico.

Journal of Archaeological Science 36, 1199-1205.

Arosio, D., 2010. A microseismic approach to locate survivors trapped under rubble.

Near Surface Geophysics 8, 623-633.

48

Bavusi, M., Rizzo, E., Lapenna, V., 2006. Electromagnetic methods to characterize

the Savoia di Lucania waste dump in southern Italy. Environmental Geology 51, 301-

308.

Bennett, M.R., Huddart, D., Gonzalez, S., 2009. Preservation and analysis of three-

dimensional footwear evidence in soils: the application of optical laser scanning. In:

Ritz, K., Dawson, L., Miller, D. (Eds.), Criminal and Environmental Soil Forensics,

Springer Publishing, pp. 445-461.

Benninger, L.A., Carter, D.O., Forbes, S.L., 2008. The biochemical alteration of soil

beneath a decomposing carcass. Forensic Science International 180, 70–75.

Bergslien, E., Bush, M., Bush, P., 2008. Identification of cremains using x-ray

diffraction analysis and a comparison to trace element analysis. Forensic Science

International 175, 218-226.

Bermejo, J.L., Sauck, W.A., Atekwana, E.A., 2007. Geophysical Discovery of a New

LNAPL Plume at the Former Wurtsmith AFB, Oscoda, Michigan. Ground Water

Monitoring & Remediation 17, 131-137.

Bevan, B.W., 1991. The search for graves. Geophysics 56, 1310-1319.

Billinger, M.S., 2009. Utilizing ground penetrating radar for the location of a

potential human being under concrete. Canadian Society of Forensic Science Journal

42, 200-209.

49

Billings, S., Wright, D., 2010. Interpretation of high-resolution low-altitude helicopter

magnetometer surveys over sites contaminated with unexploded ordnance. Journal of

Applied Geophysics 72, 225-231.

Billings, S., Youmans, C., 2007. Experiences with unexploded ordnance

discrimination using magnetometry at a live-site in Montana. Journal of Applied

Geophysics 61, 194-205.

Boudreault, J-P., Dubé, J-S., Chouteau, M., Winiarski, T., Hardy, É. 2010.

Geophysical characterization of contaminated urban fills. Engineering Geology 116,

196-206.

Brewster, M.L., Annan, A.P., 1994. Ground-penetrating radar monitoring of a

controlled DNAPL release: 200 MHz radar. Geophysics 59, 1211-1221.

Brilis, G.M., Gerlach, C.L., van Waasbergen, R.J., 2000a. Remote sensing tools assist

in environmental forensics: Part I. Digital tools - traditional methods. Environmental

Forensics 1, 63–67.

Brilis, G.M., van Waasbergen, R.J., Stokely, P.M., Gerlach, C.L., 2000b. Remote

sensing tools assist in environmental forensics: Part II. Digital tools. Environmental

Forensics 1, 1–7.

50

Bruschini, C., Gros, B., Guerne, F., Pièce, P.Y., Carmona, O., 1998. Ground

penetrating radar and imaging metal detector for antipersonnel mine detection. Journal

of Applied Geophysics 40, 59–71.

Buck, S.C., 2003. Searching for graves using geophysical technology: field tests with

ground penetrating radar, magnetometry and electrical resistivity. Journal of Forensic

Sciences 48, 5–11.

Bull, I.D., Berstan, R., Vass, A., Evershed, R.P., 2009. Identification of a disinterred

grave by molecular and stable isotope analysis. Science and Justice 49, 142-149.

Butler, D.K., 2003. Implications of magnetic backgrounds for unexploded ordnance

detection. Journal of Applied Geophysics 54, 111-125.

Caccianiga M., Bottacin, S., Cattaneo, C., 2012. Vegetation dynamics as a tool for

detecting clandestine graves. Journal of Forensic Sciences DOI: 10.1111/j.1556-

4029.2012.02071.x.

Calkin S.F., Allen, R.P., Harriman, M.P., 1995. Buried in the basement – geophysics

role in a forensic investigation. Proceedings of the symposium on the application of

geophysics to engineering and environmental problems; Denver: Environmental

Engineering Geophysical Society, 397–403.

Carter, D. O., Yellowlees, D., Tibbett, M., 2008b. Using ninhydrin to detect gravesoil.

Journal of Forensic Sciences 53, 397–400.

51

Cassidy, N.J., 2007a. A review of practical numerical modelling methods for the

advanced interpretation of ground-penetrating radar in near-surface environments.

Near Surface Geophysics 5, 5-21.

Cassidy, N.J., 2007b. Evaluating LNAPL contamination using GPR signal attenuation

analysis and dielectric property measurements: practical implications for hydrological

studies. Journal of Contaminant Hydrology 94, 49-75.

Macdonald, C.A., Ang, R., Cordiner, S.J., Horswell, J., 2011. Discrimination of soils

at regional and local levels using bacterial and fungal T-RFLP profiling. Journal of

Forensic Sciences 56, 61-69.

Cardarelli, E., Di Filippo, G. 2004. Integrated geophysical surveys on waste dumps:

Evaluation of physical parameters to characterize an urban waste dump, four cases in

Italy. Waste Management and Research 22, 390–402.

Chainey, S., Ratcliffe, J., 2008. GIS and crime mapping. John Wiley and Sons Ltd.,

Chichester, UK, 428 pp.

Cheetham, P., 2005. Forensic geophysical survey. In: Hunter, J., Cox, M. (Eds.),

Forensic Archaeology: Advances in Theory and Practice, Routledge Publishers,

Abingdon, UK, pp. 62–95.

52

Chisem, W.J., Turvey, B.E., 2007. Crime reconstruction. Elsevier Academic Press,

London, UK, 599 pp.

Combrinck, M., 2001. Transient electromagnetic exploration techniques: can they be

applied to the landmine discrimination problem? African Earth Sciences 33, 693-698.

Conyers, L.B., 2006. Ground penetrating radar techniques to discover and map

historic graves. Historical Archaeology 40, 64-73.

Curran, A.M., Prada, P.A., Furton, K.G., 2010. Canine human scent identifications

with post-blast debris collected from improvised explosive devices. Forensic Science

International 199, 103-108.

Davenport, G.C., 2001. Remote sensing applications in forensic investigations.

Historical Archaeology 35, 87–100.

Davis, J.L., Heginbottom, J.A., Annan, A.P., Daniels, R.S., Berdal, B.P., Bergan, T.,

Duncan, K.E., Lewin, P.K., Oxford, J.S., Roberts, N., Skehel, J.J., 2000. Ground

penetrating radar surveys to locate 1918 Spanish Flu victims in permafrost. Journal of

Forensic Sciences 45, 68-76.

Davis, J.L., Annan, A.P., 1989. Ground-penetrating radar for high-resolution mapping

of soil and stratigraphy. Geophysical Prospecting 37, 531-551.

53

Deans, J., Gerhard, J., Carter, L.J., 2006. Analysis of a thermal imaging method for

landmine detection, using infrared heating of the sand surface. Infrared Physical

Technology 48, 202–216.

Dekeirsschieter, J., Verheggen, F.J., Gohy, M., Hubrecht, F., Bourguignon, L.,

Lognay, E., Haubruge, E., 2009. Cadaveric volatile organic compounds released by

decaying pig carcasses (Sus domesticus) in different biotopes. Forensic Science

International 189, 46–53.

Dickinson, D.J., 1976. The aerial use of an infrared camera in a police search for the

body of a missing person in New Zealand. Journal of the Forensic Science Society 16,

205–211.

Dionne, C.A., Schultz, J.J., Murdock II, R.A, Smith, S.A., 2011. Detecting buried

metallic weapons in a controlled setting using a conductivity meter. Forensic Science

International 208, 18-24.

Donskoy, D., Reznick, A. Zagrai, A., Ekimic, A., 2005. Nonlinear vibrations of

buried landmines. Journal of the Acoustic Society of America 117, 690-700.

Douglas, A., Bowers, D., Marshall, P.D., Young, J.B., Porter, D., Wallis, N.J., 1999.

Putting nuclear-test monitoring to the test. Nature 398, 474–475.

54

Drahor, M.G., 2011. A review of integrated geophysical investigations from

archaeological and cultural sites under encroaching urbanisation in Izmir, Turkey.

Physics and Chemistry of the Earth 36, 1294-1309.

Dupras, T.L., Schultz, J.J., Wheeler, S.M., Williams, L.J., 2006. Forensic recovery of

human remains. CRC Press, 232 pp.

Ellwood, B.B., Owsley, D.W., Ellwood, S.H., Mercado-Allinger, P.A., 1994. Search

for the grave of the hanged Texas gunfighter, William Preston Longley. Historical

Archaeology 28, 94–112.

Ellwood, B.B., 1990. Electrical resistivity surveys in two historical cemeteries in

northeast Texas: a method for delineating unidentified burial shafts. Historical

Archaeology 24, 91–98.

Equitas, 2010. Methodological proposals for documenting and searching for missing

persons in Columbia. Equitas. Web: http://www.equitas.org.co/docs/45.pdf Accessed

25/01/2012/

Fenning, P.J., Donnelly, L.J. 2004. Geophysical techniques for forensic

investigations. In: Pye, K., Croft, D.J. (Eds.), Forensic Geoscience: Principles,

Techniques and Applications. Special Publication of the Geological Society of

London 232, 11-20.

55

Fiedler, S., Illich, B., Berger, J., Graw, M., 2009a. The effectiveness of ground-

penetrating radar surveys in the location of unmarked burial sites in modern

cemeteries. Journal of Applied Geophysics 68, 380-385.

Fiedler, S., Berger, J., Stahr, K., Graw, M., 2009b. Localisation of a mass grave from

the Nazi era – a case study. In: Ritz, K., Dawson, L., Miller, D. (Eds.), Criminal and

Environmental Soil Forensics, Springer Publishing, pp. 303-314.

Fitzpatrick, R.W, Raven, M.D., Forrester S.T., 2009. A systematic approach to soil

forensics: Criminal case studies involving transference from crime scene to forensic

evidence. In: Ritz, K., Dawson, L., Miller, D. (Eds.), Criminal and Environmental Soil

Forensics, Springer Publishing, pp. 105-127.

France, D.L., Griffin, T.J., Swanburg, J.G., Lindemann, J.W., Davenport, G.C.,

Trammell, V., Travis, C.T., Kondratieff, B., Nelson, A., Castellano, K., Hopkins, D.,

Adair, T., 1997. Necrosearch revisited: further multidisciplinary approaches to the

detection of clandestine graves. In: Haglund, W.D., Sorg, M.H., (Eds.), Forensic

taphonomy: the postmortem fate of human remains, CRC Press, pp. 497–509.

France, D.L., Griffin, T.J., Swanburg, J.G., Lindemann, J.W., Davenport, G.C.,

Trammell, V., Armbrust, C.T., Kondratieff, B., Nelson, A., Castellano, K., Hopkins,

D., 1992. A multidisciplinary approach to the detection of clandestine graves. Journal

of Forensic Sciences 37, 1445–1458.

56

Freeland, R.S., Miller, M.L., Yoder, R.E., Koppenjan, S.K., 2003. Forensic

applications of FMCW and pulse radar. Journal of Environmental Engineering in

Geophysics 8, 97–103.

Frohlich, B., Lancaster, W.J., 1986. Electromagnetic surveying in current Middle

Eastern archaeology – application and evaluation. Geophysics 51, 1414-1425.

Geberth, V.J., 2006. Practical homicide investigation: Tactics, procedures, and

forensic techniques. Boca Raton, Florida, CRC/Taylor & Francis.

Geradts, Z., Kelizer, J., 1996. The image database REBEZO for shoeprints with

developments on automatic classification of shoe outsole designs. Forensic Science

International 82, 21-31.

Grandjean, G. 2006. A seismic multi-approach method for characterizing

contaminated sites. Journal of Applied Geophysics 58, 87-98.

Greenhouse, J., Brewster, M., Schneider, G., Redman, D., Annan, P., Olhoeft, G.,

Lucius, J.E., Sander, K., Mazzella, A. 1993. Geophysics and solvents; the Borden

experiment. The Leading Edge 12, 261-267.

Grip, W.M., Grip, R.W., Morrison, R., 2000. Application of aerial photography in

environmental forensic investigations. Environmental Forensics 1, 121– 129.

57

Hädrich, C., Ortman, C., Reisch, R., Leibing, G., Ahlers, H., Mall, G., 2010. An

electronic body tracking dog? International Journal of Legal Medicine 124, 43–47.

Hammon, W.S. III, McMechan, G.A., Zeng, X., 2000. Forensic GPR: finite-

difference simulations of responses from buried human remains. Journal of Applied

Geophysics 115, 191-204.

Hannam, J.A., Dearing, J.A., 2008. Mapping soil magnetic properties in Bosnia and

Herzegovina for landmine clearance operations. Earth and Planetary Science Letters

274, 285–294.

Harrison, M., Donnelly, L.J., 2009. Locating concealed homicide victims: developing

the role of geoforensics. In: Ritz, K., Dawson, L., Miller, D. (Eds.), Criminal and

Environmental Soil Forensics, Springer Publishing, pp. 197-219.

Hildebrand, J.A., Wiggins, S.M., Henkart, P.C., Conyers, L.B., 2002. Comparison of

seismic reflection and ground-penetrating radar imaging at the controlled

archaeological test site, Champaign, Illinois. Archaeological Prospection 9, 9-21.

Hoffman, E.M., Curran, A.M., Dulgerian, N., Stockham, R.A., Eckenrode, B.A. 2009.

Characterization of the volatile organic compounds present in the headspace of

decomposing human remains. Forensic Science International 186, 6-13.

58

Holzer, T.L., Fletcher, J.B., Fuis, G.S., Ryerg, T., Brocher, T.M., Dietel, C.M., 1996.

Seismograms offer insight into Oklahoma City bombing. Eos Transactions, American

Geophysical Union 77:393, 398–399.

Hunter, J., Cox, M., 2005. Forensic archaeology: advances in theory and practice.

Routledge Publishers, 256 pp.

Hunter, R., Brickley, M.B., Bourgeois, J., Bouts, W., Bourguignon, L., Hubrecht, F.,

de Winne, J., Van Haaster, H., Hakbijl, T., Jong, H. de, Smits, L., Van Wijngaarden,

L.H., Luschen, M., 2001. Forensic archaeology, forensic anthropology and Human

Rights in Europe. Science and Justice 41, 173–178.

Instanes A., Lønne A., Sandaker K., 2004. Location of avalanche victims with

ground-penetrating radar. Cold Regions Science and Technology 38, 55-61.

Jervis, J.R., Pringle, J.K., Tuckwell, G.W., 2009. Time-lapse resistivity surveys over

simulated clandestine graves. Forensic Science International 192, 7-13.

Jol, H.M., 2009. Ground penetrating radar: theory and applications. Elsevier

Publications, Amsterdam, The Netherlands, 524 pp.

Juerges, A., Pringle, J.K., Jervis, J.R., Masters, P., 2010. Comparisons of magnetic

and electrical resistivity surveys over simulated clandestine graves in contrasting

burial environments. Near Surface Geophysics 8, 529-539.

59

Kenyon, J.L., 1977. Ground-penetrating radar and its application to a historical

archaeological site. Historical Archaeology 11, 48–55.

Ketterer, M.E., Czechenyi, S.C., 2008. Determination of plutonium and other

transuranic elements by inductively coupled plasma mass spectrometry: a historical

perspective and new frontiers in the environmental sciences. Spectrochimica Acta

Part B: Atomic Spectroscopy 63, 719-737.

Killam, E.W., 2004. The detection of human remains. Charles C Thomas Publishers,

Springfield, Illinois, USA, 268 pp.

King, J.A., Bevan, B.W., Hurry, R.J., 1993. The reliability of geophysical surveys at

historic period cemeteries: an example from the Plains Cemetery, Mechanicsville,

Maryland. Historical Archaeology 27, 4-16.

Komar, D.A., 1999. The use of cadaver dogs in locating scattered, scavenged human

remains: preliminary field test results. Journal of Forensic Sciences 44, 405–408.

Koper, K., 2003. http://geology.about.com/od/seismo_forensics/a/kursk.htm

Accessed: 25/01/2012/.

Koper, K.D., Wallace, T.C., Taylor, S.R., Hartse, H.E., 2001. Forensic seismology

and the sinking of the Kursk. Eos Transactions, American Geophysical Union 82:37,

45–46.

60

Lark, R.M., Rawlins, B., 2008. Can we predict the provenance of a soil sample for

forensic purposes by reference to a spatial database? European Journal of Soil Science

59, 1000-1006.

Larson, D.O., Vass, A.A., Wise, M., 2011. Advanced scientific methods and

procedures in the forensic investigation of clandestine graves. Journal of

Contemporary Criminal Justice 27(2), 149-182.

Lasseter, A, Jacobi, K.P., Farley, R., Hensel, L., 2003. Cadaver dog and handler team

capabilities in the recovery of buried human remains in the Southeastern United

States. Journal of Forensic Sciences 48, 1–5.

Lee, C.W., 2004. The nature of, and approaches to, teaching forensic geoscience on

forensic and earth science courses. In: Pye, K., Croft, D.J. (Eds.), Forensic

Geoscience: Principles, Techniques and Applications. Special Publication of the

Geological Society of London 232, 301-333.

Leighton, T.G., Evans, R.C.P., 2008. The detection by sonar of difficult targets

(including centimetre-scale plastic objects and optical fibres) buried in saturated

sediment. Applied Acoustics 69, 438-463.

Leitner, M., Kent, J., Oldfield, I., Swoope, E., 2007. Geoforensic analysis revisitied –

the application of Newton’s geographic profiling method to serial burglaries in

London, UK. Police Practice and Research 8(4), 359-370.

61

Linford, N., 2004. Magnetic ghosts: Mineral magnetic measurements on Roman and

Anglo-Saxon graves. Archaeological Prospection 11, 167–180.

Lopera, O., Milisavljević, N., 2007. Prediction of the effects of soil and target

properties on the antipersonnel landmine detection performance of ground-penetrating

radar: A Colombian study. Journal of Applied Geophysics 63, 13-23.

Lopera, O., Milisavljević, N., Lambot, S., 2007. Clutter reduction in GPR

measurements for detecting shallow buried landmines: a Colombian case study. Near

Surface Geophysics 5, 57-64.

Lovestead, T.M., Bruno, T.J., 2011. Detecting gravesoil with headspace analysis

methods with adsorption on short porous layer open tubular (PLOT) columns.

Forensic Science International 204, 156-161.

Manrong, C., Lizhong, Y., Xiangfeng, N., Bin, C. 2009. Application of environmental

magnetism on crime detection in a highway traffic accident from Yangzhou to

Guazhou, Jiansu Province, China. Forensic Science International 187, 29-33.

Marchetti, M., Settimi, A., 2011. Integrated geophysical measurements on a test site

for detection of buried steel drums. Annals of Geophysics, 54, 105-114.

Marchetti, M., Cafarella, L., Di Mauro, D., Zirizzotti, A., 2002. Ground

magnetometric surveys and integrated geophysical methods for solid buried waste

detection: a case study. Annals of Geophysics 45, 563-573.

62

Matias, H.C., Monteiro Santos, F.A., Rodruiges Ferreira, F.E., Machado, C., Luzio,

R., 2006. Detection of graves using the micro-resistivity method. Annals of

Geophysics 49, 1235-1244.

Matias, M.J., Marques da Silva, M., Goncalves, L., Peralta, C., Grangeia, C.,

Martinho, E., 2004. An investigation into the use of geophysical methods in the study

of aquifer contamination by graveyards. Near Surface Geophysics 2, 131–136.

Mazhari, S.A., 2010. An introduction to forensic geosciences and its potential for

Iran. Journal of Geography and Geology 2(1), 77-82.

McKinley, J.M., Ruffell, A., Harrison, M., Meier-Augenstein, W., Kemp, H., Graham,

C., Barry, L. 2008. Spatial thinking in search methodology: a case study of the ‘no

body’ murder enquiry, West of Ireland. . In: Ritz, K., Dawson, L., Miller, D. (Eds.),

Criminal and Environmental Soil Forensics, Springer Publishing, pp. 285-302.

Mellet, J.S., 1992. Location of human remains with ground penetrating radar. In:

Hanninen, P., Autio S., (Editors), Proceedings of the Fourth International Conference

on Ground Penetrating Radar, June 8-13; Rovaniemi, Geological Survey of Finland

Special Paper 16, 359–65.

Metje, N., Atkins, P.R., Brennan, M.J., Chapman, D.N., Lim, H.M., Machell, J. et al.

2007. Mapping the underworld – state-of-the-art review. Tunnelling and Underground

Space Technology 22, 568-586.

63

Miller, P.S., 1996. Disturbances in the soil: finding buried bodies and other evidence

using ground penetrating radar. Journal of Forensic Sciences 41, 648-652.

Millington, T.M., Cassidy, N.J., Nuzzo, L., Crocco, L., Solovieri, F., Pringle, J.K.,

2011. Interpreting complex, three-dimensional, near-surface GPR surveys: an

integrated modelling and inversion approach. Near Surface Geophysics 9, 297-304.

Milsom, J., Eriksen, A. 2011. Field Geophysics. 4th review edition. The Geological

Field Guide Series, Wiley Publishers, Chichester, 304 pp.

Missiaen, T., Söderström, M., Popescu, I., Vanninen, P., 2010. Evaluation of a

chemical munition dumpsite in the Baltic Sea based on geophysical and chemical

investigations. Science of the Total Environment 408, 3536-3553.

Missiaen, T., Feller, P. 2008. Very-high-resolution seismic and magnetic

investigations of a chemical munition dumpsite in the Baltic Sea. Journal of Applied

Geophysics 65, 142-154.

Morgan, R.M., Robertson, J., Lennard, C., Hubbard, K., Bull, P.A., 2010. Quartz

grain textures of soils and sediments from Canberra, Australia: a forensic

reconstruction tool. Australian Journal of Forensic Sciences 42(3), 169-179.

Morgan, R.M., Allen, E., Lightowler, Z.L., Freudiger-Bonzon, J., Bull, P.A., 2008. A

forensic geoscience framework and practice. Policing 2(2), 185-195.

64

Morgan, R.M., Bull, P.A., 2007a. The philosophy, nature and practice of forensic

sediment analysis. Progress in Physical Geography 31, 43-58.

Morgan, R.M., Bull, P.A., 2007b. Forensic geoscience and crime detection. Minerva

Med. Leg. 127, 73-89.

Morrison, R.D., 2000. Application of forensic techniques for age dating and source

identification in environmental litigation. Environmental Forensics 1, 131-153.

Munschy, M., Boulanger, D., Ulrich, P., Bouiflane, M., 2007. Magnetic mapping for

the detection and characterization of UXOs: Use of multi-sensor fluxgate 3-axis

magnetometers and methods of interpretation. Journal of Applied Geophysics 61,

168–183.

National Research Council, 2009. Strengthening forensic science in the United States:

A path forward. Washington, DC: National Academies Press.

Niemann, W., Olesinki, S., Thiele, T., Martens, G., Carlsen, I.C., 2002. Detection of

buried landmines with x-ray backscatter technology. Insight 44, 634-636.

Nobes, D.C., 2007. Effect of soil grain size on the geophysical response of graves:

clay vs silt vs sand. Proceedings of the International Crime Science Conference

(ISCS), 16-17 July, London, UK, http://hdl.handle.net/10092/2036 Accessed 2nd

February 2012.

65

Nobes, D.C., 2000. The search for ‘‘Yvonne’’: a case example of the delineation of a

grave using near-surface geophysical methods. Journal of Forensic Sciences 45, 715–

21.

Nobes, D.C., 1999. Geophysical surveys of burial sites: a case study of the Oaro

Urupa site. Geophysics 64, 357-367.

Novo, A., Lorenzo, H., Ria, F., Solla, M., 2011. 3D GPR in forensics: finding a

clandestine grave in a mountainous environment. Forensic Science International 204,

134-138.

Orlando, L., Marchesi, E., 2001. Georadar as a tool to identify and characterize solid

waste dump deposits. Journal of Applied Geophysics 48(33), 63–174.

Owsley, D.W., 1995. Techniques for locating burials, with emphasis on the probe.

Journal of Forensic Sciences 40, 735–740.

Pasion, L.R., Billings, S.D., Oldenburg, D.W., Walker, S.E., 2007. Application of a

library-based method to time domain electromagnetic data for the identification of

unexploded ordnance. Journal of Applied Geophysics 61, 279-291.

Persson, K., Olofsson, B., 2004. Applied geophysics in archaeological prospecting at

the Kings’ Mounds, Gamla Uppsala, Sweden. Journal of Archaeological Sciences 31,

551-562.

66

Powell, K., 2004. Detecting human remains using near-surface geophysical

instruments. Exploration Geophysics 35, 88-92.

Pringle, J.K., Jervis, J.R., Hansen, J.D., Cassidy, N.J., Jones, G.M., Cassella, J.P.,

2012a. Geophysical monitoring of simulated clandestine graves using electrical and

Ground Penetrating Radar methods: 0-3 years. Journal of Forensic Sciences doi:

10.1111/j.1556-4029.2012.02151.x.

Pringle, J.K., Holland, C., Szkornik, K., Harrison, M., 2012b. Establishing forensic

search methodologies and geophysical surveying for the detection of clandestine

graves in coastal beach environments. Forensic Science International

doi:10.1016/j.forsciint.2012.01.010.

Pringle, J.K., Jervis, J.R., 2010. Electrical resistivity survey to search for a recent

clandestine burial of a homicide victim, UK. Forensic Science International 202, e1-7.

Pringle, J.K., Cassella, J.P., Jervis, J.R., 2010. Preliminary soilwater conductivity

analysis to date clandestine burials of homicide victims. Forensic Science

International 198, 126-133.

Pringle, J.K., Lenham, J.W., Reynolds, J.M., 2009. GPR investigations to characterise

Medieval and Roman foundations under existing shop premises: a case study from

Chester, Cheshire, UK. Near Surface Geophysics 7(2), 93-100.

67

Pringle, J.K., Jervis, J., Cassella, J.P., Cassidy, N.J., 2008. Time-lapse geophysical

investigations over a simulated urban clandestine grave. Journal of Forensic Sciences

53, 1405-17.

Pye, K., Blott, S.J., 2009. Development of a searchable major and trace element

database for use in forensic soil comparisons. Science and Justice 49, 170-181.

Pye, K., 2007. Geological and soil evidence. CRC Press, Boca Raton, USA, 335 pp.

Pye, K., Croft, D.J., 2004. Forensic Geoscience: Principles, Techniques and

Applications. Geological Society of London Special Publication, London 232, 318 pp.

Rawlins, B.G., Kemp, S. J., Hodgkinson, E.H., Riding, J.B., Vane, C.H., Poulton C.,

Freeborough, K., 2006. Potential and pitfalls in establishing the provenance of earth-

related samples in forensic investigations. Journal of Forensic Sciences 51, 832-845.

Rebmann, A., David, E., Sorg, M.H., 2000. Cadaver dog handbook: forensic training

and tactics for the recovery of human remains. CRC Press, Florida, USA, 232 pp.

Redmayne, D.W., Turbitt, T., 1990. Ground motion effects of the Lockerbie air crash

impact. Geophysical Journal International 101, p.293.

Reynolds, J.M., 2011. An introduction to applied and environmental geophysics, 2nd

review edition. John Wiley and Sons, 681pp.

68

Rezos, M.M., Schultz, J.J., Murdock II, R.A., Smith, S.A., 2010. Controlled research

utilizing a basic all-metal detector in the search for buried firearms and miscellaneous

weapons. Forensic Science International 195, 121-127.

Ritz, K., Dawson, L., Miller, D., 2009. Criminal and environmental soil forensics.

Springer Publishing, 519 pp.

Rodriguez, W.C., Bass, W.M., 1985. Decomposition of buried bodies and methods

that may aid in their location. Journal of Forensic Sciences 30, 836–852.

Ruffell, A., 2010. Forensic pedology, forensic geology, forensic geoscience,

geoforensics and soil forensics. Forensic Science International 202, 9-12.

Ruffell, A., McCabe, A., Donnelly, C., Sloan, B., 2009a. Location and assessment of

an historic (150-160 years old) mass grave using geographic and ground penetrating

radar investigation, NW Ireland. Journal of Forensic Sciences 54, 382-394.

Ruffell, A., Donnelly, C., Carver, N., Murphy, E., Murray E., McCambridge, J.,

2009b. Suspect burial excavation procedure: A cautionary tale. Forensic Science

International 183, e11-e16.

Ruffell, A., Dawson, L., 2009. Forensic geology in environmental crime: illegal waste

movement and burial in N. Ireland. Environmental Forensics 10, 207-217.

69

Ruffell, A., Kulessa, B., 2009. Application of geophysical techniques in identifying

illegally buried toxic waste. Environmental Forensics 10, 196–207.

Ruffell A., McKinley J. 2008. Geoforensics. John Wiley and Sons, Chichester, UK.

332 pp.

Ruffell, A., 2005a. Burial location using cheap and reliable quantitative probe

measurements. Forensic Science International 151, 207-211.

Ruffell, A., 2005b. Searching for the IRA “disappeared”: Ground Penetrating radar

investigation of a churchyard burial site. Journal of Forensic Sciences 50, 1430-1435.

Ruffell, A., McKinley, J., 2005. Forensic geoscience: applications of geology,

geomorphology and geophysical to criminal investigations. Earth Science Reviews

69, 235-247.

Ruffell, A., 2002. Remote detection of identification of organic remains: an

assessment of archaeological potential. Archaeological Prospection 9, 115–122.

Saey, T., Van Meirvenne, M., Dewilde, N., Wyffels, F., De Smedt, P., Meerschman,

E., Islam, M.M., Cockx, L., 2011. Combining multiple signals of an electromagnetic

induction sensor to prospect land for metal objects. Near Surface Geophysics 9, 309-

317.

70

Sato, M., Hamada, Y., Feng, X., Kong, F.N., Zeng, Z., Fang, G., 2004. GPR using an

array antenna for landmine detection. Near Surface Geophysics 2, 7-13.

Sauck, W.A., Atekwana, E.A., Nash M.S. 1998. High conductivities associated with

an LNAPL plume imaged by integrated geophysical techniques. Journal of

Environmental and Engineering Geophysics 2, 203-212.

Schultz, J.J., Martin, M.M., 2011. Controlled GPR grave research: comparison of

reflection profiles between 500 and 250 MHz antennae. Forensic Science

International 209, 64-69.

Schultz, J.J., 2008. Sequential monitoring of burials containing small pig cadavers

using ground-penetrating radar. Journal of Forensic Sciences, 53, 279–87.

Schultz, J.J., 2007. Using ground-penetrating radar to locate clandestine graves of

homicide victims. Homicide Studies 11, 1-15.

Schultz, J.J., Collins, M.E., Falsetti, A.B., 2006. Sequential monitoring of burials

containing large pig cadavers using ground-penetrating radar. Journal of Forensic

Sciences 51, 607–16.

Scott, J., Hunter, J.R., 2004. Environmental influences on resistivity mapping for the

location of clandestine graves. In: Pye, K., Croft, D.J., (Eds.), Forensic Geoscience:

Principles, Techniques and Applications. London: Geological Society of London

Special Publication 232, 33–38.

71

Seed, R.B., Bea, R.G., Athanasopoulos-Zekkos, A., Boutwell, G.P., Bray, J.D.,

Cheung, C., Cobos-Roa, D., Harder, L.F., Moss, R.E.S., Pestana, J.M., Riemer, M.F.,

Rogers, J.D., Storesund, R., Vera-Grunauer, X., Wartman, J., 2008. New Orleans and

Hurricane Katrina III: The 17th Street drainage canal. Journal of Geotechnical and

Geoenvironmental Engineering, 134(5), 740.

Silvestri, S., Omri, S., 2008. A method for the remote sensing identification of

uncontrolled landfills: formulation and validation. International Journal of Remote

Sensing 29, 975-989.

Skinner, M.F, 1987. Planning the archaeological recovery of evidence from recent

mass graves. Forensic Science International 34, 267-287.

Sloan, S.D., Tsoflias, G.P., Steeples, D.W., Vincent, P.D., 2007. High-resolution

ultra-shallow subsurface imaging by integrating near-surface seismic reflection and

ground-penetrating radar data in the depth domain. Journal of Applied Geophysics 62,

281-286.

Solla, M., Riviero, B., Álvarez, M., Arias, P., in press. Experimental forensic scenes

for the characterization of ground-penetrating radar wave response. Forensic Science

International. doi:10.1016/j.forsciint.2012.01.025.

Somasundaram, S.D., Jakobsson, A., Smith, J.A.S., 2008. Analysis of nuclear

quadrupole resonance signals from mixtures. Signal Processing 88, 146–157.

72

Stanger, R., Roe, D., 2007. Geophysical surveys at the West End Cemetery,

Townsville: an application of three techniques. Australian Archaeometry 65, 44-50.

Statheropoulos, M., Agapiou, A., Zorba, E., Mikedi, K., Karma, S., Pallis, G.C.,

Eliopoulos, C, Spiliopoulou, 2011. Combined chemical and optical methods for

monitoring the early decay stages of surrogate human models. Forensic Science

International 210, 154-163.

Strongman, K.B., 1992. Forensic applications of ground penetrating radar. In: Pilon,

J. (Ed.), Ground Penetrating Radar, Ottawa: Geological Survey of Canada Paper 90-4,

203–11.

Suggs, J.A., Beam, E.W., Biggs, D.E., Collins Jr., W., Dusenbury, M.R., MacLeish,

P.P., Nottingham, K.E., Smith, D.J., 2002. Guidelines and resources for conducting an

environmental crime investigation in the United States. Environmental Forensics 3,

91-113.

Tallavó, F., Cascante, G., Pandey, M., 2009. Experimental and numerical analysis of

MASW tests for detection of buried timber trestles. Soil Dynamics and Earthquake

Engineering 29, 91-102.

Tibbett, M., Carter, D.O., 2008. Soil analysis in forensic taphonomy: chemical and

biological effects of buried human remains. CRC Press, Boca Raton, Florida, USA,

340 pp.

73

Turner, B., Wiltshire, P., 1999. Experimental validation of forensic evidence: a study

of the decomposition of buried pigs in a heavy clay soil. Forensic Science

International 101, 113–122.

Van Belle, L.E., Carter, D.O., Forbes, S.L., 2009. Measurement of ninhydrin reactive

nitrogen influx into grave soil during above ground and below ground carcass (Sus

scrofa) decomposition. Forensic Science International 193, 37–41.

Vaudelet P., Schmutz M., Pessel M, Franceschi M., Guérin R., Atteia O., Blondel A.,

Ngomseu C., Galaup S., Rejiba F., Bégassat P., 2011, Mapping of contaminant

plumes with geoelectrical methods. A case study in urban context. Journal of Applied

Geophysics 75, 738-751.

Vaughan, C., 1986. Ground penetrating radar surveys used in archaeological

investigations. Geophysics 51, 595-604.

Walkington, H., 2010. Soil science applications in archaeological contexts: A review

of key challenges. Earth Science Reviews 103, 122-134.

Walton, R.H., 2006. Cold case homicides: practical investigative techniques. Boca

Raton, Florida, CRC/Taylor & Francis.

Watters, M., Hunter, J.R., 2004. Geophysics and burials: field experience and

software development. In: Pye, K., Crofts, D.J. (Eds.), Forensic geoscience:

74

principles, techniques and applications. Geological Society of London Special

Publication 232, 21-31.

Williams, G.M., Aitkenhead, N., 1991. Lessons from Loscoe: the uncontrolled

migration of landfill gas. Quarterly Journal of Engineering Geology and

Hydrogeology 24, 191-207.

Wilson, A.S., Janaway, R.C., Holland, A.D., Dodson, H.I., Baran, E., Pollard, A.M.,

Tobin, D.J., 2007. Modelling the buried human body environment in upland climes

using three contrasting field sites. Forensic Science International 169, 6–18.

Witten, A., Brooks, R., Fenner, T., 2001. The Tulsa Race Riot of 1921: a geophysical

study to locate a mass grave. Leading Edge 20, 655–660.

Xiang, N., Sabatier, J.M., 2003. An experimental study on antipersonnel landmine

detection using acoustic-to-seismic coupling. Journal of the Acoustic Society of

America 113, 1333-1341.

Yuk, S., Kim, K.H., Yi, Y., 2006. Detection of buried landmines with x-ray

backscatter techniques. Nuclear Instruments and Methods 568, 388-392.

Zhang, Q., Al-Nuaimy, W., Huang, Y., 2007. Interpretation of borehole

magnetometer data for the detection and characterisation of unexploded bombs.

Journal of Applied Geophysics 61, 206-216.

75

Figure Captions:

Figure 1. Simplified conceptual geological model (CGM) of a murder victim’s

clandestine grave in a rural, sandy soil environment for (A) recent burial and (B) old

burial. Potential location indicators are shown. Modified from Harrison and

Donnelly (2009) and Pringle et al. (2012a).

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Figure 2. Map view examples of fixed-offset (0.25 m spaced) resistivity data over a

naked pig cadaver (left), empty grave (middle) and wrapped pig cadaver (right)

respectively that were buried in semi-urban sandy soil. Respective burial weeks are

shown. Note the low (blue) resistivity ‘plume’ was caused by conductive

decomposition fluids from the naked cadaver.

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Figure 3. Mapview example of contoured magnetic susceptibility data (SI units) over

a simulated forensic patio test site (see key for target).

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Figure 4. Ground Penetrating Radar (GPR) 450 MHz dominant frequency 2D profile

over a domestic patio (marked) identifying the locations of two forensic targets

(marked and shown).

79

Figure 5. Generalised search programme workflow (inc. = including). Note this

figure does not differentiate between target size, burial depth, soil type, burial

environment and other important case specific factors. Modified from Harrison and

Donnelly (2009).

80

81

Target(s)

Soil type:

sand clay

Remote sensing

Site workGeomorph

-ology / probing

Thermal imaging1

Special-ist

search dogs

Near-Surface GeophysicsPhoto-graphs

Infra-Red

Seis-mology /

Side-scan sonar

Cond-uctivity

Resist-ivity

GPR Mag-netics

Metal detector

Element analysis

Unmarked grave(s)Clandestine grave(s)UXOs/ IEDsWeapons

Drug / cash dumpsIllegal wasteInfluence of search environment on chosen method(s) (above) effectivenessWoods

Rural

Urban

Coastal

Underwater ²

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Table 1. Generalised table to indicate potential of search techniques(s) success for buried target(s) assuming optimum equipment configurations. Note this table does not differentiate between target size, burial depth and other important specific factors (see text). Key: Good; Medium;

Poor chances of success. The dominant sand | clay soil end-types are detailed where appropriate for simplicity, therefore not including peat, cobbles etc types (a more wide ranging summary of geophysical techniques versus soil types can be found in Reynolds, 2011). 1Time post-burial dependent. ²Water Penetrating Radar (WPR).

83