What are blood, hair, fingerprints, and semen classified as in an investigative context?

In an investigative context, blood, hair, fingerprints, and semen are classified as biological evidence. Biological evidence refers specifically to any evidence that is derived from a living organism, and includes items such as bodily fluids, tissues, and any other biological material that can provide vital information or insight into a criminal investigation.

Blood can offer DNA profiles that identify individuals, hair can sometimes provide mitochondrial DNA for lineage identification, and semen is crucial in sexual assault cases for establishing connections between suspects and victims. Fingerprints, while primarily a form of personal identification and classified under physical evidence, can sometimes also be associated with biological evidence when sweat or oil from skin is deposited.

This classification highlights the significance of these types of evidence in forensic science and law enforcement, which is critical for collecting, preserving, and analyzing evidence to establish facts in criminal cases.