CFI Evidence Collection & Chain of Custody 2 — Questions and Answers
Question 1: When packaging liquid accelerant samples for laboratory analysis, which container type is most appropriate?
- Plastic zip-lock bags
- Unlined paint cans or glass jars with airtight lids (Correct answer)
- Paper evidence bags
- Cardboard boxes with foam padding
Correct answer: Unlined paint cans or glass jars with airtight lids
Unlined metal paint cans or glass jars with airtight lids prevent evaporation and chemical contamination of liquid accelerant samples.
Question 2: A fire investigator discovers a suspicious device at the origin. Who should be contacted FIRST before the device is moved or collected?
- The fire marshal's office
- The property owner's insurance company
- A bomb disposal/EOD unit (Correct answer)
- The evidence custodian
Correct answer: A bomb disposal/EOD unit
Any suspected incendiary device must be evaluated by a bomb disposal/EOD unit before an investigator attempts to collect or move it.
Question 3: Which action is required when transferring physical fire evidence between investigators?
- A verbal acknowledgment is sufficient
- Both parties must sign and date the chain of custody form (Correct answer)
- The receiving investigator's supervisor must approve the transfer
- The evidence must be re-photographed at the transfer point
Correct answer: Both parties must sign and date the chain of custody form
Both the releasing and receiving parties must sign and date the chain of custody form to document every transfer of physical evidence.
Question 4: What is the primary purpose of collecting a control (blank) sample at a fire scene?
- To establish the scene's baseline chemical composition before the fire
- To demonstrate the investigator's thoroughness
- To compare against debris samples and isolate introduced accelerants from background hydrocarbons (Correct answer)
- To satisfy insurance documentation requirements
Correct answer: To compare against debris samples and isolate introduced accelerants from background hydrocarbons
Control samples capture the pre-existing hydrocarbon background of unburned materials so lab analysts can distinguish accelerants from naturally occurring compounds.
Question 5: Under NFPA 921, what minimum amount of fire debris is recommended when collecting samples for accelerant analysis?
- A teaspoon
- Enough to fill at least one-third to one-half of the collection container (Correct answer)
- Enough to fill the container completely
- Only the amount that shows visible charring
Correct answer: Enough to fill at least one-third to one-half of the collection container
NFPA 921 recommends filling the sample container one-third to one-half to allow headspace for volatile vapors that the lab will sample.
Question 6: A fire investigator photographs a key piece of evidence without placing a scale or ruler in the frame. What problem does this create?
- The photo cannot be admitted as evidence
- There is no way to determine the object's actual size in the image (Correct answer)
- The photo must be retaken from a different angle
- The chain of custody is automatically broken
Correct answer: There is no way to determine the object's actual size in the image
Without a scale reference in the photograph, the true dimensions of the evidence cannot be determined from the image alone.
Question 7: Which situation most likely constitutes a break in the chain of custody?
- Evidence is stored in a locked facility overnight
- Evidence is transferred to a laboratory technician who signs the custody form
- An unsealed evidence bag is found with no record of who accessed it last (Correct answer)
- Evidence is photographed multiple times during collection
Correct answer: An unsealed evidence bag is found with no record of who accessed it last
An unsealed evidence container with no documented access record represents a gap in accountability that can compromise the integrity of the evidence.
CFI Evidence Collection & Chain of Custody 2
When packaging liquid accelerant samples for laboratory analysis, which container type is most appropriate?