Unit 7B Blood Spatter

Transfer Pattern

Wet, bloody surface contacts a second surface;minimal lateral motion

→ Person steps in blood or presses hand to bloody surface

High Velocity Pattern (force? diameter? cause? shape?)

Force: 100ft per sec or greater

Diameter of droplets: smaller than 1mm

Cause: Gunshot wound, extreme worce

Shape: many satellites and spines

Medium Velocity Pattern (force? diameter? cause? shape?)

Force: 5-10ft per sec

Diameter of droplets: between 1-4mm

Cause: Blunt object (first, bat), stabbing

Shape: some satellites and spikes

Low Velocity Pattern (force? diameter? cause? shape?)

Force: 5ft per sec

Diameter of droplets: 4-8mm

Cause: Injury Passive Drops

Shape: Less pronounced satellites and spines

Passive Drop

Blood drop created solely as a result of gravity, linear pattern

→Person walking and bleeding, bloody moving object

Swipe

Blood pattern resulting from a lateral transfer from a moving source onto another surface

→ Bloody hair dragged against floor

Wipe

Smeared blood pattern created when an object moves through blood that is not completely dried

→ Trying to remove blood with a cloth

Pool of blood

A passive bloodstain, not absorbed to surface

Trail of blood

Blood stains or spatter patterns that show movement of a person or object after a blood source was present

Arterial Gush

Blood exiting under pressure from an artery, gets smaller with blood loss

→ Severed artery due to injury or attack

Expired blood

Blood from mouth or nose from air pressure, similar to high velocity spatter

→Injury causing internal bleeding, body trying to expel blood

Cast off pattern

Blood projected onto a surface as a result of being flung from an object in motion

→ Person repeatedly striking someone with a weapon

Void/shadowing

Area devoid of blood

→ Object was infront of the wall during injury but object was moved

Parent drop

The droplet from which a satellite spatter originates

Spine/spike

Elongated blood streaks radiating away from the center of a bloodstain

Satellite

Smaller droplet of blood projected from a larger drops of blood upon impact with a surface

Tail

Indicates the direction of travel

Elongation

Shape of blood stain as it related to the angle at which a blood droplet strikes a surface

Lines/Area of Convergence

Two dimensional view of the intersection of lines formed by drawing a line through the main axis atleast two drops of blood that indicated the general area of the source of the blood spatter