What does it mean when blood is transferred onto a clean surface?

The term "swipe" refers to the transfer of blood from a surface onto another surface, typically through a sliding or sweeping motion. This occurs when a bloodied object or person comes into contact with a clean surface, leaving a trace of blood in the pattern of that contact. In forensic terms, swipes can help reconstruct the events of a crime scene, as they provide insight into the movements and actions of individuals involved.

The other options represent different patterns and actions related to blood evidence. A "wipe" describes a scenario where a clean surface is used to remove or clean up blood, which does not convey the same transfer nature as a swipe. "Castoff" is associated with blood that is thrown or flung from a bloodied object during an action like swinging a weapon. "Pooled blood" indicates a collection of blood that has settled in a low-lying area, rather than being transferred to another surface. Understanding these distinctions is crucial for interpreting bloodstain patterns and their significance in forensic analysis.