What is a protocol?
• a detailed plan or procedure established by law enforcement.
• must be implemented for evidence to be admissable in court.
Processing a Crime Scene7 S’s of Crime Scene
Investigation• 1) Securing Scene
• 2) Separating
• 3) Scanning
• 4) Seeing
• 5) Sketching
• 6) Searching
• 7) Securing Evidence
Securing the Scene
• Responsibility of the first responder
• Priority #1 = everyone’s safety
• Priority #2 = preservation of evidence
• Maintain a log of who enters the crime scene
• Request experts to scene if necessary
• Medical examiner
• Bomb squad
Is a dead body present?
• If so, before the CSI unit starts their work, the Medical Examiner (Coroner) takes over.
• Confirms that the body is dead.
• Preliminary determination of the postmortem interval (PMI) - time since death.
• Photograph the body and protect/collect all trace evidence.
• Transport the body to the ME lab.
Separating Witnesses• Witnesses shouldn’t compare their accounts of the
event.
• Avoid collusion – working together to create a story
• Asked basic questions:
• When did the crime occur?
• Who called it in?
• Who is the victim?
• Can the perpetrator be identified?
• What did you see happen?
• Where were you when you observed the crime?
Scanning the Scene
• Determine where photos need to be taken
• Determine if there is a primary and secondary crime scene
Sketching the Scene
• Accurate rough sketch, including a body (if present) and all other evidence
• All objects measured from 2 fixed (immovable) points
• Label north
• Drawn to scale, which needs to be included on sketch.
• Transferred to computer program back at the station
Searching for Evidence
• Search pattern is determined
• Look for things out of place
• Common things: fingerprints, blood, hair, fibers, semen, weapons, drugs, etc.
• No such thing as too much evidence.
• As investigation proceeds, they will decide if the material is actually evidence.
• Once located, but before collected, exact location must be documented.
Securing & Collecting Evidence
• All evidence needs to be properly packaged, sealed and labeled.
• Liquids & arson remains – airtight, unbreakable containers.
• Moist biological evidence – breathable containers (so they don’t mold)
• Once dry, evidence is packaged in paper bindles, then placed in plastic or paper bags.
• Control samples must be obtained.
• Chain of Custody needs to be maintained!!!!
Securing & Collecting Evidence
• Evidence Log:
• Case #
• Item inventory #
• Description of evidence
• Name of suspect
• Name of victim
• Date & time of recovery
• Signature of person recovering evidence
• Signature of any witnesses present during collection
Authentication of Evidence
• Chain of Custody-A record of who is in possession of the evidence from the time it is collected until the time it is delivered to the court.
• Must be uniquely identified.
• Packaged in tamper-evident packaging
• Packaging must be designed to preserve the evidence.
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