1. Blood Spatter Mrs. L. Fox

2. Bloodstain Formation • Examining the pattern of the bloodstain can reveal • The direction from which blood originated • The angle at which a blood droplet struck a surface • The location or position of a victim at the time a bloody wound was inflicted • The movement of a bleeding individual at the crime scene • The minimum # of blows that were struck • The approximate location of an individual delivering the blows

3. Surface Texture • Harder & nonporous surfaces result in less spatter • Glass & smooth tile • Rough surfaces usually result in irregularly shaped stains with serrated edges • Possibly with satellite spatter

4. Tests for the Presence of Blood • Police want to answer three questions: • Is this blood? • Is it from a human? • How closely does it match the blood of the victim or the suspect?

5. Tests for the Presence of Blood • Presumptive tests for blood • Luminol: sprayed directly on bloodstained object; produces a glow when it contacts blood

6. Direction & Angle of Impact • As stain becomes more elliptical, its direction become more discernable. • Pointed end of stain faces direction of travel • The smaller the angle (compared to the surface), the more elongated the stain.

7. Impact Spatter • When an object impacts a source of blood • That spatter projected outward and away (exit wounds, for example) is called Forward Spatter • Blood coming back toward the source of the impact is Back SpatterVelocity of Spatter • Low velocity – bigger drops • Medium velocity – smaller drops • High-velocity – very fine drops, like a spray • Typically produced by gunshot or explosions

8. Other Spatter • Cast-off – created when a perpetrator raises an object to take another swing, and some of the blood is flung off the weapon • Arterial spray – created when an artery is nicked or torn, and the heart pumps it out fast