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Blood Spatter

The understanding of blood spatter patterns is not a widely recognized forensic practice. Bloodstain pattern interpretation (BPI) is commonly used in murder investigations, but could be utilized in everything from simple assault to mass murders if the number of trained professionals increased. BPI can reveal critical information into reinventing a given crime scene. Everything from the number of blows, stabs or shots a victim was given, the movement that was undergone by the victim and assailant after bloodshed began, position of objects at the crime scene and the type of weapon, if any, that was used can be uncovered.
Blood differs from water in that it is a less viscous liquid. The teardrop that is formed by rain is not formed by blood falling at an equal pace. As a result blood tends to hold the shape of a sphere throughout its flight path. Sobriety of the victim will have no significant effect on how bloodstain patterns are produced(wwwbrazoriacounty.com). By blood holding a generally geometric form the angle of impact (AOI), and eventually the point of origin (POO) can de determined. To determine the angle of impact, assuming the drop is contacting a flat surface, simply measure the width of the stain on the ground. This width will equal the diameter of the droplet in the air. The width will be equal to the short side of a right triangle. This triangle can be placed over the spatter and the angle at which the droplet traveled will be inline with the angle of the triangle(James & Eckhart, 1999). This can be recreated on a scientific calculator with the TAN option.
Now that the AOI has been determined the point from which the droplet originated from needs to be determined; in other words where was the victim at the time they began to bleed. This can be determined by drawing a line or placing a string through the long axis of 3 or more droplets. This triangulation technique will cause the lines to cross at the POO. By following the AOI to the...