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Bloodstain Evidence Manual: Practical Guide to Examination of Bloodstains and Patterns, Volume Three

NCJ Number
Judith L. Bunker
Date Published
36 pages
This document is designed to assist in processing bloodstain evidence.
The actions of motion and force upon liquid blood result in characteristic stain patterns that may be recognized and identified, which is integral to the proper evaluation of a criminal event involving bloodshed. This ability allows examiners to develop preserved scenes for further evaluation, evaluate witness statements, and prepare cases for trials. Pattern identification is a major factor in the interpretation of bloodstain evidence in the reconstruction of events involving bloodshed. Other factors are the knowledge of location and nature of injuries involved, investigative analysis, and witness statements. The cohesive properties of blood provide resistance to rupture of a blood drop. Characteristics of the landing surface must always be considered in the evaluation of bloodstain evidence. Recording the condition of bloodstains immediately upon arrival to an investigation is important. Directional flow patterns consist of a series of stains, having essentially the same shape and angle of impact from beginning to end, with the pointed or scalloped edge and/or greater degree of spatter pointing the direction of travel. The shape of stain is equal to the angle of impact of a blood drop. The narrow ends (tails and spatter) of stains point their direction of travel. Cast-off patterns occur when blood is released at the termination of motion. A cast-off pattern consists of a series of stains presented in a linear or arc-like fashion, with a more circular shape at the beginning of the pattern, becoming increasingly elongated in their direction of travel. Patterns on ceilings and walls will describe the type of swing or motion used by the source. Other stains and patterns are described, including drip, splash, and projected patterns, forceful impact spatter, spatter pattern distribution, transfer patterns, contact/compression transfer patterns, secondary transfer patterns, and pressure, transfer impression, and repetitive impression patterns. 2 footnotes, 60 illustrations