CFC Bloodstain Pattern Analysis 2 — Questions and Answers
Question 1: What term describes bloodstains produced when blood falls into existing wet blood at a scene?
- Satellite spatter
- Transfer stain
- Pool with scalloping
- Secondary spatter (Correct answer)
Correct answer: Secondary spatter
Secondary spatter occurs when a blood source (such as pooled blood) is struck or disturbed, producing additional droplets from the existing wet blood.
Question 2: A 'parent stain' in bloodstain pattern analysis refers to:
- The largest stain at the scene
- The blood source from which satellite spatter originated (Correct answer)
- A stain from the primary victim
- The central bloodstain in a pooled area
Correct answer: The blood source from which satellite spatter originated
The parent stain is the original bloodstain from which satellite droplets are projected upon impact.
Question 3: Which bloodstain pattern is most consistent with a victim who received blows while lying on the ground?
- Projected arc pattern
- Satellite spatter with no directionality
- Low-velocity impact spatter directly beneath the source (Correct answer)
- Cast-off pattern on the ceiling
Correct answer: Low-velocity impact spatter directly beneath the source
A victim lying on the ground being struck would produce low-velocity impact spatter distributed directly beneath and around the wound site.
Question 4: In BPA, what does the 'area of convergence' represent?
- The point in 3D space where blood originated
- The 2D location on a surface where spatter originated (Correct answer)
- The zone of heaviest blood deposition
- The last position of a wounded individual
Correct answer: The 2D location on a surface where spatter originated
The area of convergence is the two-dimensional region on a surface (such as a floor) where the trajectories of individual bloodstains intersect, indicating the general origin of the spatter.
Question 5: A bloodstain with a width-to-length ratio close to 1:1 (nearly circular) was most likely deposited at what angle?
- 10–20 degrees
- 30–45 degrees
- 60–75 degrees
- Near 90 degrees (Correct answer)
Correct answer: Near 90 degrees
A nearly circular stain indicates the droplet struck the surface at close to 90 degrees (perpendicular), as the sine of 90° equals 1, producing a circular shape.
Question 6: What type of pattern results from blood being projected under pressure from an arterial wound?
- Drip trail
- Gush pattern
- Arterial spurting pattern (Correct answer)
- Expirated spatter
Correct answer: Arterial spurting pattern
An arterial spurting pattern shows rhythmic, arc-shaped stains consistent with the pulsatile pressure of blood ejected from a severed artery.
Question 7: Which characteristic most reliably distinguishes expirated blood spatter from impact spatter?
- Larger average droplet size
- Presence of mucus, bubbles, or dilution from respiratory fluids (Correct answer)
- Higher density of stains per square foot
- Directional tailing pointing upward
Correct answer: Presence of mucus, bubbles, or dilution from respiratory fluids
Expirated blood often contains air bubbles, mucus, or dilution from saliva/respiratory fluids, distinguishing it microscopically and visually from impact spatter.
CFC Bloodstain Pattern Analysis 2
What term describes bloodstains produced when blood falls into existing wet blood at a scene?