Crime Scene Reconstruction: Bloodstain Pattern Analysis: BPA

In one alleged crime, investigators were forced to rely on DNA from an unlikely source. A couple had been viciously attacked with only one surviving. The survivor had identified the killer but, later retracted the statement she had made to police.

TMBA recreated the crime scene for tru TV's television program "Forensic Files" as the show searched for answers using the evidence, including essential blood pattern analysis.

Using expert testimony, such as blood spatter analysis and calculated bullet trajectories- TMBA provided a detailed 3D animation of the crime scene, including a likely scenario of the victim kneeling at the time of death, which contradicted eyewitness accounts.

An average sized adult body has five to six quarts of blood circulating. When this flow is interrupted by injuries such as bullet wounds, blunt force trauma, or a knife wound, some of the blood is released and exits the body.

If the injury is the result of a violent event, especially in the case of a shooting, blood almost always spurts or sprays out as scattered drops or in a scattered pattern. Experienced investigators collect essential evidence by "reading" the position of the blood stains and the pattern of the spatter. This insight can be crucial in determining the course of events.

Details such as the number and shape of drops of blood and the exact location of bloodstains can be studied and used to ascertain the movement of the victim at the time the injuries were sustained and to determine the movements of the alleged attacker.

Blood spatter analysis might also be used to determine the direction from which the attack came.

The proximity of the bloodstain to the victim can indicate the type of impact the victim suffered, the shape of object that created the wounds, the number of strokes inflicted and the location of the victim and offender during and after the incident.