Evidence Handling, Crime Scene, and Forensics
Evidence Handling, Crime Scene, and Forensics
This domain tests whether evidence survives from scene to court. The exam emphasizes scene control, documentation, collection, packaging, chain of custody, and forensic requests that match the question being asked.
Core rules
- First responder priorities: safety and medical care, scene preservation, suspect apprehension, and a scene log. Limit access and record everyone who enters.
- Document before you move: photographs with scale, sketches, notes, and a scene log. Record item location, condition, and who handled it.
- Use gloves and change them between scenes or items. Collect reference samples and controls where appropriate.
- Package biological evidence in paper or breathable containers after drying; never seal wet items in plastic. Package firearms and sharp objects safely and separately.
- Maintain an unbroken chain of custody: item number, description, collector, date and time, location, transfers, and storage. Each transfer should be signed and traceable.
- Forensic requests should ask a specific question: DNA on a swab, latent print development, firearms comparison, toxicology, or digital extraction.
Worked example
An expended cartridge case lies on gravel outside a barracks. Photograph it in place with a scale, note the location, collect with clean gloves, place it in a paper envelope, seal it, and write initials, date, time, and item number across the seal. Submit it for fingerprint and firearms examination; do not carry it loose in a pocket.
Traps
Packaging wet biological evidence in plastic; commingling items; losing the chain after a handoff; collecting without a reference; and overhandling items that may carry latent prints or DNA.