PROCESSING EVIDENCE

Scene of Crime Officer S.O.C.O. an officer who gathers forensic evidence at the scene of a crime. usually civilians, not police officers, but are employed by the police force. Evidence collected is passed to detectives and to forensic laboratories. The SOCOs do not investigate crimes or analyse evidence themselves.

Health and Safety Many jobs require you to wear personal protective equipment (PPE). Link to Activity 32.1A on p452

Contamination The unwanted transfer of material must be avoided at a crime scene Individuals can contaminate the scene or evidence at any time by: Leaving fingerprints / hairs / fibres / DNA Not sealing the evidence properly Putting more than one piece of evidence in a bag at once Using old equipment Contaminated evidence can not be used in a court of law and may result in criminals being set free.

Processing a Crime Scene Correct processing of a crime scene is essential to gather as much information as possible and prevent contamination. STEP 1 INTERVIEW - The SOCO arrives on the scene and makes sure it is secure. An initial walk-through is conducted to get a feel for the crime scene. The first officer at the scene and/or the victim is interviewed to ascertain the "theory" of the case; what allegedly happened, what crime took place, how was the crime committed etc. This information may not be 100% factual but it will give the SOCO a place to start from. The SOCO also needs to find out if anything has been moved. Potential evidence is noted but at this point, nothing is touched.

Processing a Crime Scene STEP 2 DOCUMENTATION – the "theory" of the case supported by what the SOCO observes. Examine the scene to identify evidence, point of entry and exit, the general layout, etc. The SOCO thoroughly documents the scene as well as any potential evidence by taking photographs and drawing sketches during a second walk-through. Sometimes, a video walk-through may be conducted. Again, nothing is touched.

Processing a Crime Scene STEP 3 PROCESSING - Now it's time to touch stuff -- very, very carefully. The SOCO systematically collects all potential evidence, tagging it, logging it and packaging it so it remains intact for further analysis by a crime laboratory. The lab processes all of the evidence collected at the crime scene. When the lab results are in, they go to the lead detective on the case.

What kind of evidence might a SOCO be searching for? Trace evidence (gunshot residue, paint residue, broken glass, unknown chemicals, drugs) Impressions (fingerprints, footprints, tool marks) Body fluids (blood, semen, saliva, vomit) Hair and fibres Weapons and firearms evidence (knives, guns, bullet holes, cartridge casings) Documents (diaries, suicide note, phone books; also includes electronic documents like answering machines, text messages)

http://www.centredessciencesdemontreal.com/static/autopsy/flash.htm http://www.crime-scene-investigator.net/collect.html