Blood spatter

What are the two sub principles of the principle of stain shape and vector correlation?

1. Directional angle 2. Impact angle

What are the six mechanisms in the pattern diversity principle?

1. Static blood dispersed from a point source 2. Blood dispersed in a jet (stream ejection) 3. Blood dispersed as a function of accelerated motion 4. Blood that accumulates or flows on a surface 5. Blood dispersed as a function of secondary contact with a surface 6. Blood dispersed as a function of gravity

Drip trail

A pattern of individual spatter deposited on a surface, demonstrating movement of the dripping item from on point to another

Blood into blood

A pattern of spatter deposited into one another or into another liquid, resulting in an accumulation with secondary spatter randomly oriented around the margin

Impact pattern

A radiating pattern of small circular or elliptical shaped stains created when blood is broken up at a source by some force

What is a void?

An absence of stains in an otherwise continuous pattern Helps the technician realize that some object was moved after the bloodshed event

The physically altered bloodstain principle

Once exposed, blood will react to environmental conditions in a predictable manner

What is the most effective way to document blood stains?

Road mapping

Drips

Spatter resulting from blood dripping from an individual or otherwise bloodied object

Cast off

Stains created when blood is flung from an object that is either in motion or which suddenly stops some motion

Corollary

The impact and directional angles for a number of stains associated with an impact event may define the origin of the stains in three dimensions

What are the three underlying principles that guide the behavior of the bloodstain pattern analyst?

The pattern diversity principle, the principle of stain shape and vector correlation, the physically altered bloodstain principle

The principle of stain shape and vector correlation

The shape of a bloodstain provides indicators as to the direction of deposition as well as the spatial origin of the blood.

The pattern diversity principle

The variations in combinations of blood volumes and forces acting on those volumes lead to recognizable classes of patterns

Gush/splash

An irregular pattern created when blood is ejected in volume

Smear

Any stain or pattern created by the transfer of blood from on object onto another, through some form of contact

Pattern transfer

Any stain or pattern created by the transfer of blood from on object to another in which a recognizable characteristic or image is present in the pattern

Spurt

Blood is ejected in a stream under pressure or with velocity Artery or the heart is breached