Forensics of Blood

After a homicide or an assault has been committed, police investigators usually find blood at the scene of the crime, giving them clues as to what happened. The blood’s texture and shape and how it is distributed around the victim often help investigators determine when the crime was committed, whether the crime was preceded by a fight between individuals, and which weapon was used say, a knife, a gun, or an object used to hit a person. But criminals have tried many ways to hide, clean up, and remove blood evidence. For example, what looks like blood may be another substance placed there by the criminal to mislead police investigators. Also, some criminals clean up the blood from the crime scene or move the victim’s body somewhere else, making it harder to reconstruct what really happened. To take these potential scenarios into account, forensic scientists who apply the latest scientific discoveries to law have developed techniques that can tell whether the