crime scene investigation & evidence collection
Post on 07-Jan-2016
48 Views
Preview:
DESCRIPTION
TRANSCRIPT
CRIME SCENE INVESTIGATION & EVIDENCE COLLECTION
CSI team and Crime lab
The Seven S’s of Cime Scene Investigation
Responsibilities of first officer1. Obtain medical assistance for anyone in need2. Arrest any perpetrators3. Exclude all unauthorized personnel4. Isolate the area5. Determine the boundaries of crime scene6. Entry and exit points of perpetrator7. Initial walk through8. Develop strategy for examining and documenting crime scene9. Determining primary and possible secondary crime scenes10. Document and photograph obvious evidence
Crime Scene Search Patterns
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
Scaled sketch of the crime scene
http://vimeo.com/45223797
The Frye Standard
Frye v. United States (1923) (polygraph test questioned)
The Frye Standard
Practical application:
Evidence
Direct Evidence
EvidenceCircumstantial (Indirect) Evidence
Locard’s Exchange Principle• Established by Dr. Edmond
Locard
Physical evidence
Biological evidence
• Control Sample:
• Standard/reference sample:
• Substrate control:
Packaging evidence
1. Create a clean paper and place evidence in the X position
2. Fold in the left and right sides, and then fold in the top and bottom
3. Put the bindle into a plastic or paper evidence bag affixing a seal over the opening
4. Write your name on the seal
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
Bagging the evidence
1. Bag the evidenceAdd identification Seal itSign it across the sealed edge
2. Sign over to a lab technician Open bag on non-sealed edge
3. Return items to the evidence bagSeal evidence bag in another bagSign the evidence log
• 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
• 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.
Crime scene reconstruction
Crime scene reconstruction involves:
Staging
When lab results don’t match up with the testimony of witnesses
Common examples:
top related