How to Interpret Blood Spatters
1) Angular - If the victim was on the move, drops hit at an angle. The more oblique the impact, the longer the drop’s tail. The head points in the direction the person was traveling.
2) High Velocity - Misty, diffuse spatter is created by external force greater than 100 feet per second — which usually means a gunshot, an explosion, or (seriously) a sneeze.
3) Hair Impact - A traumatic impact between head and surface tends to leave a stain with feathered edges, like someone squished a loaded paintbrush against the wall.
4) Hair Swipe - If the smear fades out in one direction, the head was likely bloody before contact. The lightest edge of the swipe points in the direction the head was traveling.
5) Fabric Swipe - More fluid than hair swipes, these stains sometimes display the imprint of the bloodied clothing. T-shirt weaves are often the easiest patterns to decipher.