1. Blood Spatter
Velocity and Angle

2. Effect of Surface Smooth surface = smooth sphere
Blood Spatter
Effect of Surface
Smooth surface = smooth sphere
Rough surface may cause some splatter

3. Velocity
Low impact is really blood under the influence of gravity - it just falls.
Due to air resistance, speed maxes out at distances above about 7 feet

4. Medium impact occurs when a force such as a bat is applied.

5. High impact - fine mist of droplets

6. Determining Direction of Blood
Blood Spatter > Direction
Determining Direction of Blood
If more than one drop (from spatter) results, the point of origin can be determined

8. Angle of impact

10. Angle of Impact

11. Determining Direction of Blood
Blood Spatter > Direction
Determining Direction of Blood
The angle can be determined mathematically.
Width/Length, then take the inverse sin (sin-1).
Sin ᶿ=width/length
This number is the impact angle (90 = perpendicular to surface; <10 at a sharp angle)

12. Point of Convergence – 2D
Origin of blood
Point of Convergence – 2D
Point of Origin – 3D

13. Blood Spatter > Direction
For each blood drop, a string can be guided back to the point of origin.

14. Reconstructing the crime
• With the evidence that is collected, the crime scene investigator attempts to reconstruct the crime.
• This involves trying to work out what events happened and the order that they happened.