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