Crime Scene and Death Invesigation

Crime scenes

  • Large variety of different crime scenes

  • No one way to define a crime scene but some examples include

  • Location

    • Site of original criminal activity is the primary crime scene and any subsequent locations are secondary crime scenes

    • Does not assign any priority or importance to scenes

  • Size

    • A macroscopic crime scene such a house may be composed of many microscopic crime scenes such as the rooms within the house

  • Type of crime

    • Homicide, robbery, sexual assault

  • Condition

  • Physical location

    • Indoors, outdoors, vehicles

  • Type of criminal behaviour

Processing a Crime Scene

  • As every crime scene is different, there is not one way to process a crime scene

  • Assessments and boundaries of the crime scene can and will change as the investigation proceeds

  • Objective→recognize, preserve, collect, and interpret all physical evidence at a scene

Physical Evidence

  • Forensic testing of physical evidence can provide many different kinds of information

    • Linkage between persons, scenes, and objects

      • Based on Locard’s Exchange Principle: whenever two objects come into contact there will be a mutual exchange of matter between them

    • Investigative leads

    • Information on the corpus delicti (“body of the crime”)

    • Information on the modus operandi (“mode of operating” or “M.O.”)

    • Proving or disproving witness statements

    • Identification of suspects

    • Identification of unknown substances

    • Reconstruction of a crime

Crime Scene Procedures: Scene Management

  • Crime scene requires management of

    • Information

    • Manpower

    • Technology

    • Logistics

  • Different police forces will use different models and personnel depending on demand and availability

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Crime Scene Procedures: First Responding Officer

  • Police officers, emergency medical personnel, and/or fire department are typically the first to arrive on scene

    • View the crime scene in its most original condition

    • Their actions will determine the basis for a successful or unsuccessful resolution of the investigation

  • Upon arrival safety is the primary concern then initiate crime scene measures:

    • Assist the victim

    • Search for and arrest suspect if still on scene

    • Detain any witnesses and keep the separate from each other and the scene to preserve objectivity

    • Protect and secure crime (barrier tape, official vehicles, ect.)

    • Establish a crime scene security log to record any persons entering and exiting the crime scene snd limit access

Crime Scene Procedures: Crime Scene Survey

  • Investigator will perform a preliminary scene survey or walk-through

  • Note any transient or conditional evidence that may be present that requires immediate protection and processing

  • Be aware of weather conditions

  • Note any points of entry, exit, or paths of travel within scene

  • Notify superior officers or other agencies required

Crime Scene Documentation and Forensic Photography

  • After walk-through, the scene’s condition must be documented for a permanent record before processing

  • 4 major tasks of documentation:

    1. Note taking

    2. Videography

    3. Photography

    4. Sketching

Crime Scene Documentation: Photography