1. CRIME SCENE INVESTIGATION & EVIDENCE COLLECTION

2. CSI team and Crime lab

3. The Seven S’s of Cime Scene Investigation

4. Responsibilities of first officer
Obtain medical assistance for anyone in need
Arrest any perpetrators
Exclude all unauthorized personnel
Isolate the area
Determine the boundaries of crime scene
Entry and exit points of perpetrator
Initial walk through
Develop strategy for examining and documenting crime scene
Determining primary and possible secondary crime scenes
Document and photograph obvious evidence

5. Crime Scene Search Patterns

6. photographs
Objects must NOT be removed until photographed from all angles
If anything removed it should be noted and NOT be reintroduced
Include photos of adjacent areas, close-ups of victim’s relative position in the scene and injuries
If size is significant, a point of reference should be included in the photo
Videotaping and narrating the crime scene can also be done

7. Scaled sketch of the crime scene

9. The Frye Standard
Frye v. United States (1923) (polygraph test questioned)
The Frye Standard
Practical application:

11. Evidence
Direct Evidence

12. Evidence Circumstantial (Indirect) Evidence
Locard’s Exchange Principle
Established by Dr. Edmond Locard

13. Physical evidence

14. Biological evidence

15. The Innocence Project
Beginning in 1992, used DNA to examine post-conviction cases
Faulty eyewitness identifications accounted for up to 87% of the wrongful convictions

17. Control Sample:
Standard/reference sample:
Substrate control:

18. Packaging evidence
Create a clean paper and place evidence in the X position
Put the bindle into a plastic or paper evidence bag affixing a seal over the opening
Write your name on the seal

19. Chain of Custody
Provides documentation of every person who has come into contact with the evidence
A paper trail
Demonstrates to the courts that the evidence that is being presented at trial is free of contamination, alteration, or substitution

21. Bagging the evidence
Bag the evidence Add identification Seal it Sign it across the sealed edge
Sign over to a lab technician Open bag on non-sealed edge
Return items to the evidence bag Seal evidence bag in another bag Sign the evidence log

22. Never package wet evidence while wet
Blood stained material should NOT be stored in airtight containers due to mold potential. Paper bags or wrapping paper used.
Air dry clothes and place in individual separate bags
Charred debris from fire is sealed in airtight containers

23. Facts result from collected evidence processed by the forensic lab
Lead detective aims to see how facts fit into the crime scenario
Lab results can show the reliability of witness accounts, establish identity of victim or suspects, show suspects innocence or link them with the crime.

24. Crime scene reconstruction
Crime scene reconstruction involves:

25. Staging
When lab results don’t match up with the testimony of witnesses Common examples: