Crime Scene Investigation. Defining the Crime Scene Information Obtained from a Crime Scene Processing the Crime Scene

Crime Scene Investigation


Defining the Crime Scene

Information Obtained from a Crime Scene

Processing the Crime Scene






Can be classified by: Location of Criminal Activity Size of Area Type of Crime Committed Physical Location of the Crime

Where is the crime scene?


Location of Criminal Activity

Primary = where the original crime occurred

Let’s look at an example

Secondary = subsequent crime scenes

Primary vs. Secondary

Tom Bosley

Scott Baio


Tom Bosley

Scott Baio

Primary Crime Scene


Tom Bosley

Scott Baio

Secondary Crime Scene


Size of Crime Scene

Macroscopic = one location, composed of many microscopic crime scenes

Microscopic = focuses on specific type of physical evidence

Macroscopic vs. Microscopic

Tom Bosley

Scott Baio

Macroscopic = McDonalds Area(Tom Bosley’s body, Chachi, the dumpster, etc.)


Tom Bosley

Scott Baio

Microscopic

GSR on Baio’s hand


Tom Bosley

Scott BaioMicroscopic

Tom Bosley’s Leg Wound


Type of Crime Committed Homicide, Robbery, Sexual Assault, etc.

Physical Location of Crime Scene Indoors, Outdoors, Vehicle, etc.





Info from Scene

Corpus Delicti - the body of the offenseMust be proven a crime has been committed

(i.e. dead body should be produced in murder trial)

Modus Operandi (MO) – a certain criminal’s repeated behavior.

Info from Scene

Linkage of persons, places and things Locard Exchange Principle: when two

objects come into contact with one another, an exchange of matter takes place.

Physical evidence can link suspect, victim, crime scene, and objects to one another

Info from Scene

Victim

Object

Suspect

Crime Scene

Info from SceneAll found at scene

Info from SceneBullet in Bosley

Info from SceneFingerprints on gun

Info from SceneBaio’s Hair on Bosley

Info from SceneBaio’s suspenders’ button

In dumpster

Info from Scene Proving or disproving witness statements

Can identify intentional lies Can identify unintentional eyewitness

mistakes

Identification of Suspects Fingerprints and DNA

Identification of Unknown Substances Illegal drugs, poison, anthrax

Info from Scene Corpus Delicti Modus Operendi Linking people, objects, crime scene Proving witness/suspect statements Identification of suspects Identification of unknown substances Providing investigative leads

Info from Scene

Corpus Delicti Modus Operendi Linking people, objects,

crime scene Proving witness/suspect

statements Identification of suspects Identification of unknown

substances Proving investigative leads

Reconstruction of

Crime





Processing the Crime SceneCrime Scene Investigation Models

Requires teamwork by crime scene personnel and investigators

See figure 8.1 in text the individual processing the scene depends

on the state/community

• Detectives• Patrol Officer• Crime squad

• Lab Scientist• Medical Examiner• Crime scene tech.


1. First Officer on the Scene

2. Securing the Crime Scene

3. Crime Scene Survey

4. Crime Scene Documentation

5. Searching the Crime Scene

6. Collection of Physical Evidence








First Officer on the Scene

Safety is the primary concern

Assist the victim Search for and arrest suspect Detain and separate witnesses Protect the crime scene (barrier tape) Note any changes made to the scene








Securing the Crime Scene

Anyone entering the crime scene will deposit and remove evidence. (Locard Exchange Principle)

Secure the scene with physical barriers One officer assigned to prevent entrance

of unwanted personnel Log kept of disturbances to scene








Crime Scene Survey

After the scene is secure, the investigator and first responder do a “walk-through”

Prepare an initial reconstruction Note any temporary evidence Note points of entry/exit that require attention Access scene for personnel, precautions, and

equipment needed








Crime Scene Documentation

Taking notes Videotaping Photographing Sketching


Taking Notes of the Crime Scene

Record activities including:Notification of personnel Arrival InformationScene Description (environment, evidence)Victim Description


Videotaping the Crime Scene Introduce with case #, date, location Begin with surroundings (include entrance/exits)

Tape Evidence (wide angle, close-up) Victims viewpoint

Narrate the video or discuss contents Edit original video

DO NOT:


Photographing the Crime Scene

Take examination quality photographs (used by experts to interpret evidence)

Every photo should be recorded in a log

Take with and without a scale


Sketching the Crime Scene

Goal is to record exact position of all evidence to aid in reconstruction.

Rough sketches can be refined into final sketches Three techniques of measurement are used:

X Y X Y X Y

Triangulation Baseline Polar Coordinates

e e e

30°








Searching the Crime Scene

After scene documentation, a more thorough search of the scene is completed

See table 8.3 for types of search Systematic search ensures no piece of

physical evidence is missed








Collection of Physical Evidence

One individual designated as evidence collector

Temporary, fragile, or easily lost evidence should be collected first

Evidence placed in primary and secondary containers

Collection of Physical Evidence

Liquid or volatile evidence placed in airtight containers

Biological evidence placed in non-airtight container and allowed to dry

Each item packaged separately



Lab Analysis of Evidence

After the crime scene is processed and the evidence is analyzed,

Crime Scene Reconstruction can begin

Crime Scene Reconstruction

Initial evidence leads to the formation of Hypotheses (guesses as to what happened)

Hypotheses are tested by additional analyses

Disproved hypotheses are thrown out, leaving a reconstruction theory

Case Study: Homicide Scene

VictimSuspects

Crime Scene

Documents

Crime Scene Investigation. Defining the Crime Scene Information Obtained from a Crime Scene Processing the Crime Scene