Crime Scenes

Defining the Crime Scene
1. Location
  1. Primary
    1. Initial Crime Occured
  2. Secondary
    1. Subsequent Crime Scenes
2. Size of Area
  1. Macroscopic
    1. One Location
    2. Many Microscopic Crime Scenes
  2. Microscopic
    1. Focuses on specific type of physical evidence
3. Type of Crime Committed
  1. Homicide
  2. Robbery
  3. Sexual Assault
4. Physical Location of the Crime
  1. Indoors
  2. Outdoors
  3. Vehicle
Information obtained at Crime Scene
1. Corpus Delicti
  1. body of the offense
2. Modus Operandi
  1. Certain criminal's repeated behaviour
3. Linkage of persons, places and things
  1. Locard Exchange Principle
    1. When 2 objects come into contact with one another, an exchange of matter takes places
  2. Physical evidence can link suspect, victim, crime scene and objects to one another
4. Proving or disproving witness statements
  1. identifying intentional lies
  2. identifying unintentional eyewitness mistakes
5. Identification of Suspects
  1. Physical Evidence
    1. Biological Evidence (e.g. blood, saliva, hair, semen, sweat, skin cells, fingerprints and/or palm prints), Weapons (e.g. firearm, knife, and bottle and/or baseball bat), Environmental Evidence (e.g. tyre tracks, footprints and/or broken door/window/glass)
  2. Psychological Evidence
    1. Psychological evidence is information that can provide and insight to the mind of the offender such as evidence of intent/pre-planning or a spur-of-the-moment crime of passion. It can also refer to the level of violence displayed in the crime, which has implications for trial/sentencing.
    2. Weapons brought to the scene can indicate intent compared to an apparently unplanned weapon e.g. heavy vase in a home, evidence of an attempt to clean the crime scene and remove physical evidence (e.g. weapon not at the scene; blood cleaned from scene), multiple injures on the victim/blood splatter patterns indicating frenzied attack or the use of strangulation/single wound with weapon brought to the scene.
6. Identification of Unknown substances
  1. Illegal drugs, poison, anthrax
7. Providing investigative leads
8. THIS LEADS TO THE RECONSTRUCTION OF THE CRIME
Processing the Crime Scene
1. Requires teamwork by crime scene personnel and investigators
  1. Detectives, lab scientists, patrol officers, medical examiners, crime squad and crime scene tech
2. Individual processing the scene depends on the state/community
3. First Officer on the Scene
  1. • Assist the victim(s) and provide immediate medical assistance (even if evidence is destroyed in process).
  2. • The deceased victim(s) are not cleaned up until a Forensic Officer checks for trace evidence including bloodstains, hair and other evidence.
  3. • Witnesses and suspects are found, detained and kept separate to avoid transference of trace evidence.
  4. • Crime scene is protected (perimeter marked with tape to enable logging and recording of visitors).
  5. • NOTE any changes made to the crime scene.
4. Securing the Crime Scene
  1. Anyone entering the crime scene will deposit and remove evidence. (Locard Exchange Principle)
  2. Secure the scene with physical barriers
  3. One officer assigned to prevent entrance of unwanted personnel
  4. Log kept of disturbances to scene
5. Crime Scene Survery
  1. After the scene is secure, the investigator and first responder do a “walk-through”
  2. Prepare an initial reconstruction
  3. Note any temporary evidence
  4. Note points of entry/exit that require attention
  5. Access scene for personnel, precautions, and equipment needed
6. Crime Scene Documentation
  1. Taking Notes
    1. Record activities including: Notification of personnel, arrival Information, scene Description (environment, evidence), victim Description
  2. Videotaping
    1. Introduce with case number, date, location, begin with surroundings (include entrance/exits), tape Evidence (wide angle, close-up), victims viewpoint. Do not: Narrate the video or discuss contents, edit original video
  3. Photographing
    1. Take examination quality photographs (used by experts to interpret evidence), every photo should be recorded in a log, take with and without a scale
  4. Sketching
    1. 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: triangulation, baseline and polar coordinates.
7. Searching the crime scene
  1. After scene documentation, a more thorough search of the scene is completed, systematic search ensures no piece of physical evidence is missed
8. Collection of Physical Evidence
  1. One individual designated as evidence collector, temporary, fragile, or easily lost evidence should be collected first, evidence placed in primary and secondary containers
  2. Liquid or volatile evidence placed in airtight containers, biological evidence placed in non-airtight container and allowed to dry, each item packaged separately
Crime Scene Reconstruction
1. Initial evidence leads to the formation of Hypotheses (guesses as to what happened)
2. Hypotheses are tested by additional analyses
3. Disproved hypotheses are thrown out, leaving a reconstruction theory
the difference between organised and disorganised criminals
1. Organised: Crime is planned; attempt to control victim; leaves few clues; victim a targeted stranger; above average IQ; socially/sexually competent; usually living with partner; experiencing anger/depression at time of the offence; follows media coverage of offence.
2. Disorganised: little planning or preparation; random disorganised behaviour; minimum use of restraints; little attempt to hide evidence at crime scene; lives alone, near crime scene; sexually and socially inadequate; experiences severe forms of mental illness; physically or sexually abused in childhood; frightened/confused at time of attack.
two difference approaches to offender profiling
1. Top-down approach: used by the FBI in America. Uses a large database of previous information to help solve similar crimes. Looks for statistical patterns and trends. Associated with Robert Ressler among others.
2. Bottom-up approach as used in the UK. Connects the behaviour at the crime scene with everyday behaviour of the offender. Associated with the work of Professor David Canter.

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