FRSC 1011 - Collection of Crime Scene Evidence

Overview of Crime Scene Evidence

• Physical Evidence: Objects establishing a crime has been committed or linking a crime to a victim or perpetrator.
• Importance of recognizing and preserving physical evidence at the crime scene.

Types of Physical Evidence

• Biological: Blood, semen, saliva.
• Documentary: Written documents relevant to the case.
• Chemicals: Drugs, explosives.
• Trace Evidence: Fibers, hairs, powders, soil.
• Impression Evidence: Fingerprints, tool marks, shoeprints.
• Miscellaneous: Glass, firearms, paint.

Evidence Collection Procedures

• Visible vs. Trace Evidence: Ensure both visible items and potential carriers of trace evidence are collected (e.g., clothing, vacuumings).
• Contamination Prevention: Use latex/nitrile gloves, disposable forceps, sanitized tools.

Packaging Evidence

• Keep items in separate containers to prevent damage and contamination.
• Recommended materials include:
  • Unbreakable containers (e.g., pill bottles) for trace evidence.
  • Manila envelopes or paper bags for biological materials.
• Important Note: Never use ordinary mailing envelopes as they leak fine particles.
• For biological materials, allow air-drying before packaging to prevent mold.
• DNA Evidence: Requires strict protocols to avoid contamination (e.g., use of face masks and gloves).

Chain of Custody

• Establishes continuity of possession of evidence from crime scene to court.
• Essential for validating evidence presented in court, ensuring integrity and proper handling throughout the investigative process.

Obtaining Reference Samples

• Standard samples (e.g., blood or hair from a suspect) are crucial for comparison with crime-scene evidence.
• Ensures accurate analysis and strengthens the case.

Submitting Evidence

• Evidence can be delivered in person or via mail, with careful packaging to prevent damage.
• Accompany evidence with detailed submission forms for laboratory analysis.

Crime Scene Safety

• Investigators face unknown biological hazards; protective gear is essential (e.g., gloves, masks, protective clothing).
• Maintain awareness of sharp objects and use biohazard bags for disposal of contaminated materials.

Collection Techniques

• Various techniques depending on evidence type:
  • Foot/Tool Impressions: Use dental stone for preservation.
  • Biological Evidence: Utilize sterile swabs and collection protocols.
  • Powders and Soils: Use scoopulas for transfer.
  • Fingerprint Collection: Utilize fingerprint powders and lifting tape.

Legal Considerations in Search and Seizure

• Adhere to Fourth Amendment protections against unreasonable search and seizure.
• Understand scenarios where warrantless searches may be justified (emergency, evidence destruction risk, incident to lawful arrest, or consent).

Case Study: O.J. Simpson Investigation

• Timeline of events leading to evidence collection and subsequent challenges in maintaining evidence integrity.
• Highlights from the case include:
  • Presence of blood and DNA evidence linking Simpson to the victims.
  • Challenges faced with evidence collection procedures and defense claims about evidence handling.
• Impact on forensic protocols and importance of proper evidence collection and management in investigations.

Review of Key Points

• Understanding of physical evidence types, collection methods, chain of custody, and legal frameworks within forensic investigations is critical for all crime scene investigators.