Bloodstain Pattern Analysis

Introduction: When investigating a crime scene, many different variables are taken into account such as fingerprints, any other forms of DNA, or even clues left behind at a crime scene. Even looking at blood splatter, the forensic technician can conclude an estimated guess to the weapon used, the height of the person, whether it was foul play or not, and even if it was passive patterns or projected patterns. Blood splatter analysis becomes important when recreating a crime scene (Peschel). Bloodstain pattern analysis comes into play; and that is the interpretation of bloodstains at a crime scene in order to recreate the actions that caused the bloodshed (“A Simplified Guide”).

High-speed photography of blood drops impacting different target surfaces
This was however not the case for wallpaper where the blood could be seen moving up and down the bloodstain before finally forming the bloodstain. This may have been due to the amount of friction the blood encountered when moving along the surface – there would not have been much friction force in the case of the cardboard, however on the wallpaper, because it is a textured surface, there would have been a greater friction force. Given this finding, it would have been expected that the time taken for a bloodstain to form on the wood surface would have taken approximately the same time as the time taken for a bloodstain to form on wallpaper. This was however not the case, with the bloodstain forming in only 39.6 ms on wood. It was seen in the high-speed video of a bloodstain forming on wood that the blood travelled continuously in a downward direction meaning no extra time was spent with blood moving up and down the bloodstain. The bloodstains that took the shortest amount of time to form had the longest wave