Crime Scene Investigation

Crime Scene Investigation

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

Defining the Crime Scene Where is the crime scene? Can be classified by: • Location of Criminal Activity • Size of Area • Type of Crime Committed • Physical Location of the Crime

Defining the Crime Scene Location of Criminal Activity • Primary = where the original crime occurred • Secondary = subsequent crime scenes Let’s look at an example

Primary vs. Secondary Tom Bosley Scott Baio

Primary vs. Secondary Tom Bosley Primary Crime Scene Scott Baio

Primary vs. Secondary Tom Bosley Secondary Crime Scene Scott Baio

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

Macroscopic vs. Microscopic GSR on Baio’s hand Tom Bosley Microscopic Scott Baio

Macroscopic vs. Microscopic Tom Bosley’s Leg Wound Tom Bosley Microscopic Scott Baio

Defining the Crime Scene • 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 offense • Must 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 Suspect Victim Object Crime Scene

Info from Scene All found at scene

Info from Scene Bullet in Bosley

Info from Scene Fingerprints on gun

Info from Scene Baio’s Hair on Bosley

Info from Scene Baio’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 Scene Crime 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.

Processing the Crime Scene • First Officer on the Scene • Securing the Crime Scene • Crime Scene Survey • Crime Scene Documentation • Searching the Crime Scene • 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

Crime Scene Documentation Taking Notes of the Crime Scene • Record activities including: • Notification of personnel • Arrival Information • Scene Description (environment, evidence) • Victim Description

Crime Scene Documentation Videotaping the Crime Scene • Introduce with case #, 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

Crime Scene Documentation 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

Crime Scene Documentation 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 30° e e e Triangulation Baseline Polar Coordinates

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

Crime Scene Investigation • Processing the Crime Scene • 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 Crime Scene Victim Suspects

Crime Scene Investigation