What is the most common type of spatter found at a crime scene?

• A. Cast-off
• B. Back spatter
• C. High-velocity spatter
• D. Passive spatter

Answer: (A)

Cast-off spatter occurs when a bloody weapon is swung and blood is flung from the edge of the weapon onto nearby surfaces. This pattern is commonly found at crime scenes involving a weapon because each strike can deposit blood on the weapon and then cast it off as the weapon changes direction. You’ll often see multiple droplets or lines on walls, ceilings, or furniture that line up with the direction of the blows, which makes this type of spatter a frequent finding in indoor assaults.

Back spatter is associated with the firearm’s energy traveling back toward the shooter, and high-velocity spatter comes from gunshots as a fine mist; those are more specific to shootings. Passive spatter results from blood dripping under gravity, which happens, but the distinctive, repeatable cast-off patterns from a weapon strike are more commonly observed across many cases, making cast-off the typical type investigators look for.