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Processing a Crime Scene Protocol for the Crime Scene Unit

Processing a Crime Scene Protocol for the Crime Scene Unit

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Processing a Crime Scene

Protocol for the Crime Scene Unit

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

Seeing the Scene

• Photograph the overall crime scene

• Close-up photos with a ruler

Crime Scene Photos

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

Crime Scene Sketch

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.

Search Methods

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.

The End