Mr. Chapman Forensics 30

 Direct Evidence – includes firsthand observations such as eyewitness accounts or police dashboard video cameras.  Direct evidence includes what witnesses said, heard, or did, and confessions are included as direct evidence.

 Circumstantial evidence – indirect evidence that can be used to imply a fact but that DOES NOT DIRECTLY PROVE IT.  Circumstantial evidence on its own is almost NEVER enough to directly convict a person of committing a crime.

 TRACE evidence is a form of circumstantial evidence, and the one that most people are the most familiar with.  CIRCUMSTANTIAL evidence can be found in one of two ways:

 Physical Evidence: includes fingerprints, footprints, shoe prints, tire impressions, and tool marks.  Generally, physical evidence reduces the number of suspects to a very small group.  Exception: Fingerprints are generally as condemning as forms of biological evidence.

 Biological Evidence: includes body fluids, hair, plant parts, and natural fibres.  Biological evidence is typically the most persuasive type of evidence in court, as it can narrow the suspects to an extremely small group of people, or even one individual.

 Class evidence: narrows an identity to a group of persons or things. For example, if Type A blood is found at the scene, that narrows the group of suspects to anyone with Type A blood.  Individual evidence: narrows the field to a single person or thing. A fingerprint is an example of individual evidence.

Who is involved in a crime scene investigation?

 Usually the first to arrive at a crime scene.  May require that a district attorney be present to determine whether a search warrant is necessary for the crime-scene investigators.

 Document the crime scene in detail and collect physical evidence.  CSIs include:  Recorders: to record the data  Sketch artists: to sketch the scene

 Photographers: to take photos of the crime-scene.  Other, general evidence collectors.

 Medical Examiners: also known as coroners, and may be necessary to determine the cause of death.  Detectives: look for leads by interviewing witnesses and talking to the crime-scene investigators about the evidence. Notice that the CSIs don’t do this!

 Entomologists  Forensic scientists  Forensic psychologists  All these specialists may be consulted if their expertise are required.

1. What type of evidence most closely resembles individual evidence – physical or biological? 2. What are two different types of crime- scene investigators? 3. What is a detective’s role at a crime- scene?