How is a transfer stain formed?

A transfer stain is formed when a blood-contaminated object makes contact with a surface, leaving a mark or impression of the blood. This can occur when someone touches or moves an object that has blood on it, such as a hand, shoe, or a piece of clothing. As the object makes contact, the blood is transferred to another surface, resulting in a stain that can provide valuable forensic evidence regarding the events that transpired.

This process is distinct from other types of blood stains, such as those created by falling blood, splattering, or pooling, as those involve different mechanisms of blood movement and deposition. Transfer stains can often indicate the actions of individuals at a crime scene and are crucial for reconstructing events. Forensic investigators can analyze these stains to determine both their origin and the nature of the interaction that resulted in the transfer, making them significant in forensic science investigations.