# Comparing Forensic Science (Blood Spatter And Bullet Trajectory)

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 Forensic science (blood spatter and bullet trajectory) Crime scene reconstruction often involves the examination of blood spatter which may help to determine how the crime occurred. The angle of impact (angle at which the bloodstain hit the floor), point of convergence and point of origin (the point from where the blood left the body) all need to be discovered and hence the position of the body of the victim when the incident occurred can be worked out. The force of the impact on the body determines the size of the blood drops. A low velocity force, created by something like a hammer or blunt instrument will create larger drops whereas a high velocity force from something like a bullet will create a spray of smaller droplets. The shape…show more content…
The length and width of the bloodstain are measured and trigonometry using the sine function is used to determine the angle of impact. The width is line O on the triangle in Figure 26 and the length is line H. Thus we can use the sine function to work out angle a: and thus . 30° is the angle of…show more content…
a bullet hole is found in the front seat of a car, 4 feet above the ground. During its trajectory, the bullet went through the window and then into the seat. The bullet seems to have come from an apartment across the street but it is not clear which floor or window the bullet was fired from. Using a laser beam, forensics projected a line of the approximate trajectory from the building to the car using the hole in the car window and the bullet hole in the seat as reference points. They also measured the distance from the car to the building as 720 inches (60 feet). To work out the position of the shooter, the distance between him and the bullet hole in the car seat must be worked out. This requires at least two reference points (in this case the holes in the seat and the window) from which forensics can project a line back to the shooter. To determine the distance between the shooter and the bullet hole in the car seat a direct relationship is set up using right angles (see Figure 28 ). We can measure the horizontal distance from the broken window (23.5 inches) to the bullet hole and compare this distance to the diagonal length of the bullet path from the hole in the window to the hole in the seat (23.9 inches). Using these figures we can set up a