In any violent crime, there is bound to be blood. Whether it is from a stabbing, a gunshot, or being beaten to death, blood is bound to be present at the crime scene.
BPA (blood pattern analysis) is used a crime scene to “recreate the actions that caused the bloodshed” (“A Simplified Guide”). Analyzers use a number of clues (shape, size, distribution, location) to help them determine the things that occurred or did not occur.
In the image above, blood has been spattered on the wall. Examiners can look at this pattern to determine where the person it came from was located when they were hit.
BPA uses biology, physics, and mathematics to answer the questions investigators ask when blood is present at a scene. These questions include:
- “Where did the blood come from?”
- “What caused the wounds?”
- “From what direction was the victim wounded?”
- “How were the victim(s) and perpetrator(s) positioned?”
- “What movements were made after the bloodshed?”
- “How many potential perpetrators were present?”
- “Does the bloodstain evidence support or refute witness statements?”
Even though the patterns of blood may seem completely random and impossible to decipher a story of what happened from, highly trained blood analyzers know how to examine the blood to figure out what happened. Analyzers look at spatters, transfers, and voids to determine what happened. The lack of blood can be just as telling as the presence of blood. Angle of the blood spatter, how dry it is, and the shapes or prints left in the blood can help investigators determine what happened at the scene of crime. This is why blood analysis is very important – it can prove or disprove what happened at a crime and can also determine who was or was not involved in the crime. It is important to proving guilt as well as innocence.
Source: “A Simplified Guide To Bloodstain Pattern Analysis.” Forensic Science Simplified. 2013. Web. 9 Dec. 2015.