Sample managemen tby kananika

SAMPLE MANAGEMENT

BY ARON YOHANA KANANIKA (BSc.Ed (Hons), MBA(F&B)

FORENSIC BUREAU CID HQ DSM

POSTMORTEM TOXICOLOGY

• Postmortem toxicology is used to determine whether alcohol, drugs or other poisons may have caused or contributed to the death of a person.

CASE INVESTIGATION

• Often the investigating officer will not know whether or not any offence has been committed until the results of the forensic toxicological analyses are available,

• Details of the circumstances that lead to the conclusion that a criminal action might have taken place must be supplied to the toxicologist so that the analyses can be planned.

Guides to the collection of Physical Evidence

Specimen Evidence

Identification

Wrapping and packing

Remarks

Blood : Liquid for toxicological use

2-5 ml of blood and preservative mixture

Label ,stopper and seal.Investigator initials

Use universal sterile bottle

Preservative desired. Refrigerate. Can freeze.

Drugs 1. Liquids

All Label and seal.Investigator initials

Make sure container does not leak. Seal.

2. Powders, pills and solids (found in paper bags)

All to 30 gm

Label and seal.Investigator initials

Seal with tape to prevent any loss

Place them in plastic bags to prevent any loss.

Guides to the collection of Physical Evidence, cont.

Specimen

Evidence (Amount)

Identification


Remarks

Urine 20-50 ml of urine

Label , stopper and seal.Investigator initials

Use sterile bottle. Seal tight with lid.

Preservative not desired. Refrigerate.

Liver Half the liver, 800 gm


Use wide mouthed sterile glass bottle. Seal tight with lid

Preservative desired. Refrigerate.

Kidney One kidney





Specimen

Evidence (Amount)

Identification


Remarks

Stomach aspirates

All Stomach aspirates


Use wide mouthed sterile glass bottle. Seal tight with lid.


Food remains and poisoned food

Send adequate Food remains and poisoned food


Pack in clean strong brown papers.



Specimen

Evidence (Amount)

Identification


Remarks

Entire stomach and its contents

Entire stomach and its contents lingered at both ends.




Portion of small intestine

Portion of small intestine lingered at both ends.





Specimen

Evidence (Amount)

Identification


Remarks

Stomach aspirates

All Stomach aspirates




Food remains and poisoned food

Send adequate Food remains and poisoned food





Specimen

Evidence (Amount)

Identification


Remarks

Poisons Send adequate amount of poison



Contaminated utensils

All Label and seal.Investigator initials


Traditional/ native medicine

Send adequate plant parts i.e. root, leaves, flowers, etc.



Use air drying for preservation.

Detection and Identification of Explosive Residues

• Post Explosion Residues

• Post – explosion investigations are difficult to

conduct as most of the physical evidence has

been destroyed, scattered or unrecognizably

distorted.

• The unreacted explosive that remains is usually

very limited in quantity and is highly

contaminated with various types of debris such

as wood, plaster, soil, metal, dirt and other

debris.

Collection of samples

• The remaining traces of explosives are mixed with soil, masonry, wood, plastic, fabrics, metal and other debris.

• The unconsumed explosives, if present, are usually not visible to the naked eye, so that the successful collection of explosives residues depends upon taking the debris which are most likely to contain them.

• The location of the bomb detonation site (epicenter) must be found, and soil and other debris from the interior of the blast seat should be scraped out, and sent for analysis, since these debris are most likely to contain undetonated explosive residues.

• Types of debris which are readily penetrated by flying particles, like wood, plastics, rubber and other soft materials are especially likely to contain explosive residues.

• Even metal objects found in close proximity to the bomb site have been found to contain explosives residues, and should therefore be collected.

• A part of bombing device itself, if available, is usually a good source for the recovery of explosives residues.

Collected debris are packed and labeled and brought to the laboratory for further examination and analysis.

The following are some commonly used solvents for recovering

traces of explosives:Solvent Type of explosive Comment

water Inorganic e.g. nitrates, chlorates, per chlorates

slow to evaporate

Methanol

Organic e.g. nitrate esters, nitro aromatics, nitramines

Toxic, poor volatility

Ethanol Organics e.g. nitrate esters, nitroaromatics, nitramines

Poor volatility

Acetone Good solvent for organics, especially nitrocellulose

Good volatility, but leaves aqueous residue unless dried thoroughly

Isopropanol

organics Moderate volatility

Ethyl acetate

Good solvent for a wide range of explosives

Available in high purity

Methyl t-butyl ether

Organics Good volatility

Diethyl ether

Organics Good volatility, but serious fire hazard.

THE USE OF DNA TECHNOLOGY IN

CRIMINAL INVESTIGATION IN

TANZANIA.

Applications of DNA technology

• In criminal investigations scientists utilize DNA profile of a charged person and compare it against DNA (human biological samples) from the crime scene.

• For instance; Murder case Rape cases Paternity cases Mass disaster – plane crash, fire accidents,

massacre,

TYPES OF SAMPLES RECEIVED

• Biological samples such as blood, buccal swab, semen, sweat in clothes, hair and saliva are usually received and used to extract/obtained sufficient quantities of DNA.

EVIDENCE SAMPLES AT CRIME SCENE LIKELY TO CONTAIN

DNA

S/N Exhibit Place where DNA can be found

Source of DNA

1 Knives, Handles and blades of knives

Sweat, blood & skin

2 A cap Inner lining Sweat, hair, dandruff

3 Spectacles/glasses

Nose bridge & earlobe

Sweat, skin

4 Toothpicks, toothbrush

Edge of toothpicks, depris in toothbrushes

Saliva

Cont..

5 Cigarette, cigar pipes

Cigarette butts, cigar pipes’ mouth piece

Saliva

6 Bottle, glass, cans, bowls, cups

Rims and edges of bottles, cans, bowls, cups

Saliva, sweat

7 Stamps, envelopes

Saliva on envelope seal

saliva

8 Guns, Handles, trigger and burrel

Sweat & blood

9 Clothes underpants, shirts, trousers, dresses, sheets, socks,

Blood, semen, sweat, dandruff, hair

Cont…

10 Foot wear

Foot wear, socks Sweat & blood

11 Vehicles

Car seats, seat belts, steering wheel, tires, window glass, door knobs, buttons, rear mirrors etc…

Sweat, blood, hair, fingerprints & saliva

12 Body parts

Kidney, liver, intestines, bones

Blood & tissues

13 Toilets Toilet bowls, seats and floor

Feaces, urine

Responsibility of crime investigators handling DNA

samples;

– The investigative officer must accept the responsibility for seeing that the right types of samples are received to the DNA laboratory

– The point is that the evidence samples should not be exposed to any possibility of destruction, mishandling, contamination, and any other conceivable catastrophe that can be brought on by human or natural error.


samples …..– The point is that the evidence samples

should not be exposed to any possibility of destruction, mishandling, contamination, and any other conceivable catastrophe that can be brought on by human or natural error.


samples …..• The DNA Scientist has to work with what

has been submitted to the Laboratory ad the results will depend on the quality of the sample/evidence submitted.

• The investigating officer at the crime scene should observe the following guidelines:

GUIDELINES FOR INVESTIGATING OFFICERS

• Careful observation of the crime scene prior to handling any evidence samples must be followed

• Store crime scene memory in the form of photographs or drawings


• Isolate/seal the crime scene using police warning tapes until forensic experts arrive

• Collecting of evidence samples should be performed by either qualified personnel (crime scene examiner) or Government Chemist laboratory experts


• Collect all possible evidence (materials) that may link a suspect to a crime scene.

• Store gathered information in writing (e.g. note books etc).

• Use appropriate sampling kits in collecting DNA evidence samples.

GUIDELINES Cont…

• Appropriate sampling kits should be utilized in collecting evidence samples

• Safety and occupational health guidelines such as the wearing of gloves, shoes and masks should be observed

• Collect all the possible evidence (materials) that may link a suspect to a crime scene

GUIDELINES Cont…

• Store the gathered information either in writing or computer etc…

• Usually blood or buccal swab samples are taken from the suspected perpetrators so as to perform DNA analysis test for profile matching to crime scene samples

Storage and securing of evidence samples;

• Evidence samples should be stored according to the case file

• Evidence samples should be stored separately and appropriately labeled to avoid contamination of samples

• Evidence samples should then be locked away in a secured room

Storage and securing of evidence samples cont…..

• Buccal swab evidence samples should be dried out and stored at room temperature whilst raw blood evidence samples should be refrigerated. This is crucial as DNA samples last for an indefinite period of time when preserved properly.

Handling of Raw blood (5-10mls);

• A white sterile cotton cloth should be used to soak-up the splattered blood at the crime scene. This cloth should then be air dried and placed in a clean paper envelope.

• Blood samples should be packaged in a sterile dry glass bottle mixed with anticoagulant such as sodium fluoride.

Handling of Dried Blood;

• Scrap off the dried out blood using a clean scalpel and transfer it to a clean paper envelope.

• Alternatively, a white sterile cloth moistened with distilled water can be used to wipe off the dried blood and then air dried and stored in a clean paper envelope.

Packaging and labeling of evidence samples;

• Evidence samples must be out of harm's way

• The type of evidence samples must be indicated

• There should not be more than one label • Permanent (water insoluble) marker

pens should be used in labeling samples

Transportation of DNA evidence samples to DNA

profiling laboratories;

• DNA evidence samples have to be properly sealed/ packaged and labeled so as to prevent them from being tempered with.

• The DNA samples must be accompanied with appropriate authoritative forms (e.g., PF 180)

Information which should accompany the samples

– The type and amount of evidence samples

– The origin of the sample

– The type of crime committed

– The type of testing requested

– The name and signature of the head of investigation

Information which should accompany the samples cont…– The name of the deliverer of the

samples

– DNA samples for parentage identification must have referrals from court orders, registered advocates or Social welfare.

Conditions under which evidence samples are rejected by DNA laboratories include;

• Missing labels on evidence samples• Absence of authoritative forms, PF180, permitting

the legal handling of evidence samples• Unlabelled or destroyed labels on evidence

samples • Evidence samples not listed in the. PF. 180. • Plastic packaging of evidence samples is not

allowed as this may cause degradation of the biological material of interest

Conditions under which evidence samples are rejected by DNA laboratories include;

• Dirty packaging of evidence samples

• Unpreserved evidence samples

• More than one label (single labeling scheme) on evidence samples

FACTORS WHICH MAY AFFECT DNA EVIDENCE

• There are several environmental factors that can affect DNA’s integrity

– Heat, sunlight, moisture, bacteria and mold.

– Therefore, not all DNA evidence samples can be useful for DNA tests

FACTORS WHICH MAY AFFECT DNA EVIDENCE

• There are several environmental factors that can affect DNA’s integrity

– Heat, sunlight, moisture, bacteria and mold.

– Therefore, not all DNA evidence samples can be useful for DNA tests

FIRE SCENE INVESTIGATION

Fire Scene InvestigationsAims:• Identify the seat of

fire• Determine the cause

of fire • Collect and preserve

physical evidence • Investigate the

witness statements at the scene.

Significance of Physical evidence

• Physical evidence is any physical or tangible item that tend to prove or disprove a particular fact or issue.

Methods of collection Samples of evidences

• Physical evidence should be thoroughly documented before it is moved.

• These are field notes, written reports, sketches, diagrams, with accurate measurements and photography.

• Diagramming and photographing should always be accomplished before the physical evidence is moved or disturbed.

Methods of collection, cont.

1. Collection of Liquid Samples

• Collected with a new syringe, eye dropper, pipette, siphoning device, or the evidence container itself.

• Sterile cotton balls or gauze pads may also be used to absorb the liquid and should be sealed in an airtight container.


2 Collection of Liquid Evidence Absorbed by Solid Materials including soils and sands.

• by scooping them with the evidence container itself or by cutting, sawing, or scraping.

• nail holes, cracks, and other similar areas of wood, plaster, or even concrete are good areas to sample.

• In case of soil or sand, the liquid accelerant may absorb deeply into the material. Therefore remove samples from a greater depth.


3. Collection of solid samples for accelerant testing

• Solid accelerant may be common household materials and compounds or dangerous chemicals.

• Comparison samples.


4. Canine team• To assist with the location and

selection of samples.• It should be confirmed by

laboratory analysis


5. Collection of electrical equipment and system components.

• Electrical switches, receptacles, thermostats, relays, junction boxes, electrical distribution panels, are often collected as physical evidence.


6. Collection of Appliance or Small Electrical Equipment.

• This type of physical evidence may include diverse items, from the large (e.g. furnaces, water heaters, stoves, washers, dryers) to the small ( e.g. toasters, coffee pots, radios, irons, lamps).

Contamination of Physical evidence

1. Use of contaminated evidence containers. Use new and uncontaminated evidence containers.

2. Cross - contamination of evidence collection containers during storage and transportation. The containers should remain sealed during storage and transportation.

Contamination of Physical evidence, cont.

Therefore, during collection. • New gloves should always be used

during the collection of each item of liquid or solid accelerant evidence.

• Similarly, any collection tools such as brooms, shovels, etc, should be cleaned thoroughly and used to collect physical evidence.

Evidence Containers

• Like the collection of the physical evidence itself, the selection of an appropriate evidence container also depends on the physical state, physical characteristics, fragility, and volatility of the physical evidence.

Evidence cont. Containers,

• Liquid and Solid Accelerant Evidence Containers

Metal cans and glass jar (new and clean)

• In order to allow space for vapours to collect, the can should be not more than two-thirds full.

Evidence cont. Containers,

• Special Evidence Bags• Designed specifically for liquid and solid

accelerant evidence.• Unlike common plastic evidence bags, these

special evidence bags do not have a chemical composition that can cause erroneous test results during laboratory examination and during testing of physical evidence contained in such bags.

Identification of Physical Evidence

• All evidence should be marked or labeled for identification at the time of collection.

• These include name of the fire investigator, the date and time of collection, an identification name or number, the case number and item designation, a description of the physical evidence and where the physical evidence was located.

Transportation and Storage of Physical Evidence.

• Transporting of volatile or hazardous materials the investigator should ensure that evidence is protected from extremes of temperature.

• Freezing or heating of the volatile materials may affect lab test results. Generally , the lower the temperature at which the evidence is stored, the better the volatile sample will be preserved, but it should not be allowed to freeze.

Storage of Evidence

• It should always be protected from loss, contamination, and degradation.

• Heat, sunlight, and moisture are the chief sources of degradation of most kinds of evidence.

• Dry and dark conditions are preferred, and the cooler the better.

• Refrigeration of volatile evidence is strongly recommended.

Chain of Custody of Physical Evidence

• It is necessary to pass chain of custody from one person to another, it should be done using a form on which the receiving person signs for the physical evidence.

Evidence to look for

• Cigarette-match combinations

• Candles

• Chemicals: phosphorous, metallic sodium, potassium permanganate, and others.

• Matches. Unburnt matchbooks could carry fingerprints, so handle them carefully.

• Flammable liquids: gasoline, kerosene, paint thinner, acetone, and others.

• .

Evidence to look for, cont.

• Bottles used to hold flammable liquids.

• Other containers that could have held flammable liquids in the structure and on the grounds.

• Glass used to focus the sun's rays, more common in grain and forest fires than in structural fires.

• Tampering with gas-burning equipment.

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• THANK YOU FOR YOUR ATTENTION

Technology

Sample managemen tby kananika