Crime Scene Investigation Evidence Collection Lessons from the

Crime Scene Investigation & Evidence Collection

Lessons from the Jon. Benet Ramsey Case ► In 1996, six year-old Jon. Benet Ramsey was found murdered in the basement of her home. ► This crime scene reveals how important it is for crime scene investigators to secure a crime scene immediately or valuable information may be lost forever. ► To this day, the case remains unsolved.

Goal of Crime Scene Investigation ► Recognize, ► The document and collect evidence collected at a crime scene is all investigators have to go on to recreate a picture of what happened at the scene.

Principle of Exchange ► First described by Dr. Edmond Locard (sometimes called Locard’s Exchange Principle) ► Defined as the physical transfer of materials such as hair, fibers, blood, and skin cells when two people come in contact with each other ► The longer (or more intense) the contact, the greater amount of trace evidence

Types of Trace Evidence ► Animal or human hair ► Fingerprints ► Soil or plant material (pollen) ► Body fluids (mucus, semen, saliva, blood) ► Fiber or debris from clothing ► Paint chips, broken glass, chemicals (drugs, explosives)

Types of Evidence ► Direct evidence – includes firsthand observations, such as eyewitness accounts or police dashboard video cameras and confessions ► Circumstantial evidence – indirect evidence that can be used to imply a fact, but does not directly prove it - provides a link between a crime scene and a suspect

Circumstantial Evidence ► Can be physical or biological ► Physical evidence– includes fiber, weapons, bullets, and shell casings § Reduces the number of suspects to a specific smaller group of individuals ► Biological evidence – includes body fluids, hair, plant parts, and natural fibers § Makes the group of suspects very small, or reduces it to a likely individual § More persuasive in court

Class Evidence vs. Individual Evidence ► Class evidence – narrows an identity to a group of persons or things (ex. ; blood type) ► Individual evidence – narrows an identity to a single person or thing (ex. ; fingerprints)

Crime Scene Investigative Team ► Police officers ► District attorney ► Crime scene investigators, including recorders, sketch artists, photographers, evidence collectors ► Medical examiners ► Detectives ► Specialists (entymologist, forensic psychologist, toxicologist)

Analysis of Evidence ► Forensic labs process the evidence and send the results to the lead detective ► Unlike CSI, lab techs are specialized and only process one type of evidence ► Test results lead to crime scene reconstruction

Crime Scene Reconstruction ► Involves forming a hypothesis of the sequence of events from before the crime was committed through its commission. ► Investigators look at evidence and attempt to determine how it fits into the overall crime scenario.

Staged Crime Scenes ► Create problems for investigators because the evidence does not match witness testimony ► Examples of staged crime scenes § Arson § Suicide/murder § burglary

Procedure to Use if Staged Scene is Suspected Initially treat all deaths as homicides ► Do the type of wounds match the weapon used ► Could the wounds be self-inflicted? ► Establish a profile of the victim through family and friends ► Evaluate behavior of victim prior to the event ► Evaluate behavior of suspects prior to the event ► Corroborate statements with evidential facts ► Reconstruct the event ► Conduct forensic examinations ►