FDC Evidence Collection & Preservation 3

Question 1

Touch DNA evidence, which involves trace epithelial cells, is MOST susceptible to loss during collection due to:

Accepted Answer

Secondary transfer from an intermediate surface to the collector's hands

Answer

Touch DNA can undergo secondary transfer, where cells move from one surface to another (including the collector's hands), resulting in a mixed or misleading profile.

Question 2

Which biological stain on a garment is MOST likely to remain typeable after repeated machine washing cycles?

Accepted Answer

Semen stains due to sperm head resilience

Answer

Spermatozoa heads contain tightly packaged protamine-stabilized DNA that resists mechanical and chemical degradation better than most other biological materials.

Question 3

At an outdoor crime scene, environmental factor most damaging to biological evidence DNA integrity over a 72-hour period is:

Accepted Answer

UV radiation causing pyrimidine dimers and strand breaks

Answer

UV radiation induces pyrimidine dimer formation and direct strand breaks in DNA, causing irreversible chemical damage that prevents complete PCR amplification.

Question 4

Under SWGDAM guidelines, a forensic DNA laboratory must retain case evidence for a minimum period AFTER which of the following events?

Accepted Answer

Final legal disposition of the case

Answer

Evidence retention timelines under SWGDAM and FBI QAS guidelines are tied to final legal disposition so evidence remains available for appeals and post-conviction review.

Question 5

When swabbing a firearm for touch DNA evidence, the collector should prioritize which areas of the weapon?

Accepted Answer

High-contact areas such as the trigger, grip, and slide

Answer

The trigger, grip, and slide are the surfaces most frequently and firmly contacted during handling, maximizing the deposit of epithelial cells available for touch DNA analysis.

(FDC) Forensic DNA Certification Practice Test

(FDC) Forensic DNA Certification Practice Test

FDC Evidence Collection & Preservation 3