Bloody Surfaces: The Effects of Fabrics on the Surface of Wounds and Their Bloodstain Patterns Open Access
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A 30-year-old woman was found stabbed in her home. She was found lying face down and the stab entrance wounds were found in the back of her denim jacket. There were slight bloodstain patterns on the wall next to her but due to the placement of the stab wound in the jacket, the bloodstain pattern analysis did not correlate. Bloodstain pattern analysis (BPA) is the interpretation of bloodstains at a crime scene to piece together the events following up to the blood being shed. There are many factors that go into distinguishing a certain bloodstain, such as size, shape, and location of the stain. Bloodstains are classified into three basic types: passive stains, transfer stains, and impact stains. The type of pattern that this study focuses on is the impact stain, which is distinctive of blood projecting through the air and landing as a "spatter" on a surface. As for the surfaces, the texture on which blood lands matters significantly, however, for the 30-year-old woman, it was not what the blood landed on that mattered but where the blood could not go through. More so, this experiment focuses on the cast-off bloodstain that comes from the weapon and the person pulling away from the object. This project analyzes the different textures that may be found on a person, specifically when they are stabbed. These different textures such as cloth, denim, leather, etc. were placed on a blood-soaked sponge with a perimeter surrounding it, and immediately differences in the bloodstains were visible. The aspects explored were the type of impact spatter that is acquired from various textures on a bloody sponge, the velocity of the force impacting a bloody surface and the effect of the number of blows, and finally the effect of the size of the weapon.