Criminalistics ch 4

crime scene reconstruciton

used to support a likely sequence of events at a crime scene by observing physical evidence/statements

Blood pattern

-direction in which blood originated from

-angle which droplet struck surface

-movement of bleeding individual

-minimum number of blows that struck bleeding victim

-location of individual delivering blows that produced bloodstain

satellite stain

smaller bloodstain that originated during formation of parent stain resulting from blooding impacting surface

angle of impact

angle relative to plane of target where blood drop strikes target

spatter

airborne blood drop created when external force is applied to blood

impact- object striking blood

forward- projected away from blood source ex) exit wound

backward- projected backward from blood source ex) entry wound

area of coverage

location of 2 dimension space where directions of blood spatter can be retraced

area of origin

3-dimensional space from which blood was projected

-show position of individual in which splatter took place

string method

1. find area of coverage for stain pattern

2. place pole as axis coming from area of origin

3. attach 1 end of string to pole, and attach other to droplet to determine angle

   1. view are of origin where drops and string connect

drawback affect

back spatter striking gunman after shot and enter gun muzzle

cast-off

blood covered objects fling blood onto nearby surface

-helps suggest object used/direction (left vs right)

projected pattern

victim suffers injury to main artery/heart ejection of blood from hydraulic pressure

expiration- blood forced by airflow out nose, wound

void- absence of blood in continuous blood pattern

transfer stain- object with blood touches another object and contaminates

“feathering” amount of pressure applied to blood surface

stains/patterns

flow- pattern made by drops flowing with pull of gravity

perimeter stain- altered stain of edge characteristics- center parts removed

drip tail- blood dripping into other liquid/vice versash

shape/stain- can help determine direction a person was going