Blood Spatter Investigation

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Humans must lose approximately 40 percent of their total blood volume before they are at risk of death from blood loss (Venosa). In a criminal investigation blood spatter analysts help by attempting to assist in the reconstruction of alleged events. Their job is crucial for helping investigators in order to determine the sequence of events that created the bloodstains. Interestingly, the first study of blood stains involved the merciless beating of rabbits to death (Bevel). Contrary to popular belief, blood spatter analysis is not a new technique for the investigation of crimes. Blood spatter analysts recreate crime scenes and are able to help solve an investigation based on the reconstruction of the events. In fact, a large number of high …show more content…

A crime scene where a serious fatality has happened is going to have some degree of bloodstain evidence at the scene. However, the amount will vary depending on the situation of the crime. Blood, consisting of three types, is categorized based on passive, transfer or impact stains, each having unique characteristics such as the speed in which they leave the body or the type of force harming the blood source. Passive stains inherit drops, generally resulting from gravity behaving on a wounded body. Transfer stains on the other hand result from objects coming into contact with preexisting blood spatter. They leave blood patterns behind like a bloody shoe print or a smear from a body being dragged, for example. Impact stains result from blood projecting through the air and are usually seen as spatter, more passive force applied to the victim being harmed. Once the types of stains have been determined, the analysts proceed to reconstructing the crime. The angle and direction of every spatter is analyzed. As the angle of impact changes, so does the appearance of the resulting stain. For example, a smooth surface, such as tile, will cause little effect of the drop, whereas a rougher surface, such as carpet or concrete, disrupts the surface of the blood drops. The location and volume of the stains influence significantly how much information can be obtained. A high volume of blood, such as if the person bled to death, can often give less critical information than multiple more detailed spatter patterns. Too much blood can disguise spatter or make stain patterns unrecognizable. In contrast too little blood can give little or no valuable information. Nevertheless, every drop of blood tells its own

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