NCJ Number
214127
Date Published
2006
Length
24 pages
Annotation
Following a brief history of bloodstain pattern interpretation and a discussion of the characteristics of liquid blood, this paper discusses basic bloodstain pattern types and how they can be produced in the course of a homicide.
Abstract
Bloodstain pattern interpretation involves three areas of analysis: the shape of the individual bloodstains, the size of the individual bloodstains, and the distribution and concentration of a bloodstain pattern. The shape of the individual bloodstain may allow its origin to be determined in three dimensions. The size of the individual bloodstains suggests the nature of any impact energy that may have produced them; and the distribution and concentration of a bloodstain pattern may suggest the distance between the origin of the blood and the surface upon which it was deposited. This can be important in differentiating between impact spatter, blood expelled from the mouth and/or nose, and blood from an open artery. In examining these aspects of bloodstain interpretation in more detail, this paper discusses target surface characteristics and its effects on bloodspatter, bloodstain characteristics (shape, impact angle, and size), and blood deposited by various means and at various speeds. The latter discussion addresses blood spattered from low-, medium-, and high-velocity impacts; bloodstain patterns from projected blood (arterial bleeding); cast-off bloodstain patterns; bloodstain patterns from blood expelled through the mouth and/or nose; and transfer bloodstain patterns. The paper concludes with a discussion of the recovery and documenting of bloodstain pattern evidence (photography and lifting bloodstain pattern evidence). 36 figures and 8 references