1. Processing a Crime Scene
Protocol for the Crime Scene Unit

2. What is a protocol?
a detailed plan or procedure established by law enforcement.
must be implemented for evidence to be admissable in court.

3. Processing a Crime Scene 7 S’s of Crime Scene Investigation
1) Securing Scene
2) Separating
3) Scanning
4) Seeing
5) Sketching
6) Searching
7) Securing Evidence

4. 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

5. 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.

6. 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?

7. Scanning the Scene Determine where photos need to be taken
Determine if there is a primary and secondary crime scene

8. Seeing the Scene Photograph the overall crime scene
Close-up photos with a ruler

9. Crime Scene Photos

10. 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

11. Crime Scene Sketch

12. 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.

13. Search Methods

14. 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!!!!

15. 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

16. 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.

17. The End