CSI - Crime Scene Investigator Firearms and Ballistics Evidence Questions and Answers Flashcards

What elements are the forensic markers for gunshot residue (GSR)?

Answer: Lead, barium, and antimony particles from primer combustion

The characteristic combination of lead, barium, and antimony from primer combustion is the standard forensic marker for identifying GSR.

How are GSR samples properly collected from a suspect's hands for laboratory analysis?

Answer: With adhesive carbon stubs for SEM-EDX analysis

Adhesive carbon stubs collect GSR particles for scanning electron microscopy with energy dispersive X-ray (SEM-EDX) analysis.

How quickly should GSR samples be collected from a suspect after a shooting incident?

Answer: Within 4-6 hours, as GSR is easily lost through hand washing or normal activity

GSR dissipates rapidly through hand washing, contact with surfaces, and normal activity, making prompt collection essential.

What does a 'through-and-through' bullet wound mean for a crime scene search?

Answer: It means the bullet exited the body and the projectile may be located beyond the victim

A through-and-through wound means the projectile exited the body and is likely embedded in walls, floors, or objects beyond the victim.

What does the absence of GSR on a suspect's hands definitively prove?

Answer: Nothing definitive, as GSR may have been removed by washing or lost over time

GSR can be lost through hand washing, time passage, and environmental transfer, so its absence alone is not conclusive proof of non-involvement.

What is the examination of tool marks on firearm components used to establish?

Answer: Manufacturing marks, modifications, and comparisons linking a weapon to specific components or crimes

Firearms toolmark examination analyzes marks left by manufacturing tools and use to identify, compare, and link weapons to crimes.