Bloodstain Pattern Analysis (BPA), one of several specialties in the field of forensic science, involves the study and analysis of bloodstains at a known or suspected violent crime scene with the goal of helping investigators draw conclusions about the nature, timing and other details of the crime.
The use of bloodstains as evidence is not new; however, new experts have claimed to be able to use fluid dynamics, physics, and other calculations to determine with accuracy previous events at a crime scene. For example, the shape of blood droplets might be used to draw conclusions as to how far away the victim was from a gun when they were shot.
This technique of forensic science has drawn more skeptical scrutiny since 2000; large amounts of the body of work in BPA is done by crime investigators using subjective hunches rather than scientists from other disciplines. A report released by The National Academy of Sciences in 2009 highlighted several incidents of blood spatter analysts to overstate their qualifications as well as questioned the reliability of their methods in the courtroom.
