FRSC 1011H Lecture Notes - Lecture 9: Skeletonization
7 May 2018
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Bloodstain Pattern Analysis
Bloodstain pattern interpretation may uncover
● The direction from which blood originated
● The angle at which a droplet hit a surface
● The location or position of a victim
● The movement of a bleeding individual
● Approximate number of blows
● Approximate location of an individual delivering blows
Classifying Impact Spatter
● Low velocity
○ 4mm or more 5 feet per second
● Medium velocity
○ 1-4 mm 5-25 feet per second
● High velocity
○ Less than 1 mm 100 feet per second or faster
● In general, one should use stain size categories very cautiously and from
descriptive purposes only in evaluating impact patterns
Sources of Blood Spatter
● Impact spatter
● Cast-off spatter
● Arterial spray spatter
Skeletonization
● Occurs when the edges of a stain dry to the surface
● This usually occurs within 50 seconds of deposition of droplets, and longer for
larger volumes of blood
Drop Trail Patterns
● The pattern may show direction and speed or movement, lead to a discarded
weapon, or provide identification of the suspect by their own blood
Documenting Evidence
● Grid method
○ A grid of squares of known dimensions are set up over the entire pattern
● Perimeter ruler method
