ETC Storage & Preservation 3 — Questions and Answers
Question 1: Which packaging material is CONTRAINDICATED for storing arson evidence containing volatile accelerants?
- New, unused metal paint cans
- Glass containers with lids
- Plastic bags (Correct answer)
- Nylon-lined metal cans
Correct answer: Plastic bags
Plastic bags allow volatile accelerants to permeate through the bag walls, causing loss of evidence and potential cross-contamination.
Question 2: Under what circumstances should a wet item of clothing be stored in a paper bag rather than a plastic bag?
- When it contains trace fibers
- When it is still moist and biological evidence may be present (Correct answer)
- When it is suspected to have accelerant residue
- When it is a dark color
Correct answer: When it is still moist and biological evidence may be present
Wet clothing with biological evidence must be stored in paper (breathable) bags to allow moisture to evaporate and prevent mold that destroys DNA.
Question 3: What is the maximum recommended storage time for urine drug evidence samples at 4°C before analysis?
- 24 hours
- 3 days
- 7 days (Correct answer)
- 30 days
Correct answer: 7 days
Urine drug samples are generally stable at 4°C for up to 7 days; longer storage requires freezing to prevent bacterial growth and compound degradation.
Question 4: An evidence room log shows two items with identical property numbers. What is the BEST immediate action?
- Discard the duplicate entry
- Quarantine both items and initiate an audit (Correct answer)
- Assign a new number to one item and continue
- Transfer one item to another case
Correct answer: Quarantine both items and initiate an audit
Duplicate property numbers indicate a cataloging error; both items must be quarantined and audited to determine the correct association before any further action.
Question 5: Which type of evidence requires storage in a humidity-controlled environment to prevent cracking or warping?
- Metal shell casings
- Wooden tool handles and document paper (Correct answer)
- Glass fragments
- Synthetic fibers
Correct answer: Wooden tool handles and document paper
Wood and paper are hygroscopic materials that expand, crack, or warp with humidity fluctuations, which can alter tool mark patterns and obliterate handwriting impressions.
Question 6: A blood sample collected at a crime scene in a gray-top (sodium fluoride) tube is PRIMARILY used to preserve evidence related to:
- DNA profiling
- Alcohol and drug analysis (Correct answer)
- Toxicological heavy metal screening
- Blood typing only
Correct answer: Alcohol and drug analysis
Gray-top tubes contain sodium fluoride, a glycolytic inhibitor that prevents post-collection fermentation of glucose into alcohol, preserving blood alcohol evidence.
Question 7: When evidence must be transferred between jurisdictions, what document MUST accompany the physical evidence?
- A photograph log
- An evidence transfer receipt signed by both parties (Correct answer)
- A crime lab request form
- A copy of the incident report only
Correct answer: An evidence transfer receipt signed by both parties
An evidence transfer receipt signed by both the releasing and receiving parties documents the chain of custody during inter-jurisdictional transfers.
ETC Storage & Preservation 3
Which packaging material is CONTRAINDICATED for storing arson evidence containing volatile accelerants?