RO Forensic Science & Analysis 3 — Questions and Answers
Question 1: What type of wound characteristic indicates a close-contact or contact gunshot wound?
- A clean, circular entry wound with no surrounding discoloration
- Soot deposition, stippling, and muzzle contusion around the entry wound (Correct answer)
- A large exit wound with no entry wound visible
- Symmetric bruising around the wound margins
Correct answer: Soot deposition, stippling, and muzzle contusion around the entry wound
At contact or near-contact range, burning gases and unburned powder produce soot, tattooing (stippling), and muzzle stamp marks on the skin.
Question 2: In forensic ballistics, what is a 'comparison microscope' used for?
- Measuring the diameter of bullet holes in targets
- Viewing two bullets or cartridge cases simultaneously side-by-side to match striations (Correct answer)
- Magnifying powder residue on a shooter's hands
- Inspecting barrel rifling for manufacturing defects
Correct answer: Viewing two bullets or cartridge cases simultaneously side-by-side to match striations
A comparison microscope optically links two stages so examiners can directly compare tool marks on bullets or cases to determine if they came from the same firearm.
Question 3: Which of the following is a primary concern when collecting lead bullet fragments from a berm for forensic analysis?
- Fragments must be demagnetized before packaging
- Cross-contamination between rounds from different incidents must be prevented by segregating collection areas (Correct answer)
- All fragments must be melted down to a uniform ingot for laboratory testing
- Only fragments larger than one inch are forensically significant
Correct answer: Cross-contamination between rounds from different incidents must be prevented by segregating collection areas
Berms accumulate rounds from many different shooters and incidents, so precise location marking and separate packaging are critical to avoid cross-contaminating evidence.
Question 4: What information does a breech face impression on a fired cartridge case provide investigators?
- The chamber pressure at the moment of firing
- Individual tool marks unique to a specific firearm's bolt or slide face (Correct answer)
- The brand and lot number of the ammunition
- The distance from which the firearm was fired
Correct answer: Individual tool marks unique to a specific firearm's bolt or slide face
Machining marks on the breech face are transferred to the case head upon firing and are sufficiently unique to identify a specific firearm.
Question 5: When a range officer must preserve a shooting position as an incident scene, which action is MOST important?
- Immediately police the brass to prevent it from being a tripping hazard
- Establish a perimeter, prevent access, and notify law enforcement before touching anything (Correct answer)
- Remove the target frames so they can be used as evidence later
- Photograph only the injured party before police arrive
Correct answer: Establish a perimeter, prevent access, and notify law enforcement before touching anything
Establishing a perimeter and notifying law enforcement preserves scene integrity; any alteration before investigators arrive can compromise the forensic value of the scene.
Question 6: What does 'stippling' or 'tattooing' on skin near a gunshot wound indicate?
- The wound is an exit wound
- Unburned or partially burned powder grains struck the skin, indicating an intermediate firing range (Correct answer)
- The firearm was equipped with a suppressor
- The bullet tumbled before impact
Correct answer: Unburned or partially burned powder grains struck the skin, indicating an intermediate firing range
Stippling is caused by partially burned powder particles embedding in or abrading the skin surface and only occurs within a limited distance from the muzzle.
Question 7: Why is blood spatter analysis relevant to a range officer investigating an accidental shooting on the range?
- It determines the caliber of the bullet used
- It helps establish the relative positions of shooter and victim and the sequence of events (Correct answer)
- It identifies the manufacturer of the ammunition
- It confirms whether the firearm was cleaned recently
Correct answer: It helps establish the relative positions of shooter and victim and the sequence of events
Bloodstain pattern analysis reveals directionality, impact angle, and movement, helping reconstruct the spatial relationship between parties at the time of the incident.
RO Forensic Science & Analysis 3
What type of wound characteristic indicates a close-contact or contact gunshot wound?