1. Blood Spatter Analysis
Bloodstains and Blood Spatter are used to reconstruct events that caused the bleeding.

2. Bloodstain Patterns can tell us….
Direction from which blood originated
Angle at which a blood droplet struck a surface
Location or position of a victim at the time a bloody wound was inflicted
Movement of a bleeding individual at the crime scene
Minimum number of blows that struck a bleeding victim
Approximate location of an individual delivering blows that produced a bloodstain pattern

3. When determining the location the blood came from….
Surface texture
Shape
Size
location

4. Surface Texture
Harder and nonporous surfaces (glass, or smooth tile) -less spatter.
Rough surfaces (wood, carpet) - irregularly shaped stains with serrated edges. Possibly with satellite spatter.

5. Satellite Spatter
Small drops of blood around the perimeter of a drop or pool of blood. Produced as a result of blood impacting the target surface.

6. Direct and Angle of Impact

7. Direction of Impact
The pointed end of a bloodstain always faces its direction of travel.

8. Blood Spatter
A shooting may be characterized by both forward spatter from an exit wound and back spatter from an entrance wound.

9. Cast-off pattern
A Cast-off pattern is created when a blood-covered object flings blood in an arc onto a nearby surface.

10. Types of Blood Spatter High velocity < 1mm
Medium Velo medium velocity = 1-3 mm low velocity >3 mm
Ex. Gun shot blunt trauma (knife, bat) blood dripping

11. Blood Spatter High Velocity < 1 mm Medium Velocity 1-3 mm
Ex: Gun shot wound
Medium Velocity 1-3 mm
Ex: Blunt trauma (knife, bat)
Low Velocity > 3mm.
Ex: Dripping from wound

12. Void pattern
Created when an object blocks the deposition of blood spatter onto a target surface or object.
Examples: fingerprints, handprints, footprints, footwear prints, tool prints, and fabric prints in blood.

14. Transfer pattern
Created when a surface that carries wet blood comes in contact with a second surface.

15. Cre-Creating a Spatter Guide
We are going to be completing:
Part I, II and VII

16. Conclusion Activity
Example:

17. 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).
This number is the impact angle (90 = perpendicular to surface; <10 at a sharp angle)

18. Determining Direction of Blood
If more than one drop (from spatter) results, the point of convergence (2-D) can be determined

19. Blood Spatter > Direction
For each blood drop, a string can be guided back to the point of origin (3-D).

20. 11/19 Objective:  Review for Crime Scene Sketching and Blood Spatter Test
DMA: Which blood drop would have the lowest angle of impact?
A B C D