OIC Evidence Collection & Preservation 2 — Questions and Answers
Question 1: When photographing a fire scene for evidence, what is the correct sequence for capturing images?
- Start at the area of origin and work outward
- Start at the perimeter and work inward toward the origin (Correct answer)
- Photograph only the most damaged areas first
- Focus exclusively on structural damage before any other elements
Correct answer: Start at the perimeter and work inward toward the origin
Investigators should photograph from the exterior perimeter inward toward the area of origin to document the overall scene before close-up details.
Question 2: Which type of container is MOST appropriate for collecting liquid accelerant samples from a fire scene?
- Plastic zip-lock bags
- Paper bags
- Unlined paint cans or glass jars with airtight lids (Correct answer)
- Cardboard boxes lined with newspaper
Correct answer: Unlined paint cans or glass jars with airtight lids
Unlined paint cans or glass jars with airtight lids are used for liquid accelerant samples because they do not absorb or react with the evidence.
Question 3: What is the primary purpose of establishing a chain of custody for collected evidence?
- To speed up laboratory analysis
- To ensure evidence has not been tampered with and is admissible in court (Correct answer)
- To reduce the number of people handling evidence
- To determine the estimated cost of damage
Correct answer: To ensure evidence has not been tampered with and is admissible in court
Chain of custody documents every person who handled the evidence, ensuring its integrity and admissibility in legal proceedings.
Question 4: A fire investigator finds a suspicious burn pattern on a floor. Before sampling, what should be done first?
- Collect the sample immediately to prevent contamination
- Photograph and document the pattern in place before disturbing it (Correct answer)
- Notify the media of the finding
- Remove surrounding debris to isolate the pattern
Correct answer: Photograph and document the pattern in place before disturbing it
Evidence must be photographed and documented in its original position before any collection to preserve the scene's integrity.
Question 5: Which action would MOST likely compromise the integrity of physical evidence at a fire scene?
- Wearing nitrile gloves during collection
- Using a clean, uncontaminated tool for each sample
- Placing wet debris in sealed plastic bags for extended storage (Correct answer)
- Labeling each container before sealing
Correct answer: Placing wet debris in sealed plastic bags for extended storage
Sealing wet debris in plastic bags promotes mold growth and biological contamination, potentially destroying volatile evidence.
Question 6: When is a comparison (control) sample collected at a fire scene, and why?
- After the suspect sample to avoid cross-contamination
- From an unburned area similar to the suspect area, collected at the same time, to identify background chemicals (Correct answer)
- Only when requested by a prosecutor
- From the most heavily burned area to compare maximum damage
Correct answer: From an unburned area similar to the suspect area, collected at the same time, to identify background chemicals
Control samples from unaffected areas help the lab distinguish between accelerants and naturally occurring background chemicals in building materials.
Question 7: Under Oregon law, when a fire investigator seizes evidence from a private property without a warrant, under what general condition is this typically permissible?
- Whenever the investigator believes arson has occurred
- When exigent circumstances exist, such as active scene investigation immediately post-fire (Correct answer)
- After obtaining verbal consent from a neighbor
- Only if the property is abandoned
Correct answer: When exigent circumstances exist, such as active scene investigation immediately post-fire
Post-fire investigations on private property generally require a warrant unless exigent circumstances or valid consent exist, as established in Michigan v. Tyler.
OIC Evidence Collection & Preservation 2
When photographing a fire scene for evidence, what is the correct sequence for capturing images?