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Quantitative Blood Stain Analysis: Differentiation of Contact Transfer Patterns Versus Spatter Patterns on Fabric via Microscopic Inspection

NCJ Number
Date Published
April 2015
8 pages
This study examined the differences between “contact transfer” and “spatter” bloodstain patterns on clothing.
In crime scene reconstruction, it is often necessary to differentiate “contact transfer” and “spatter” bloodstain patterns found on clothing. Current methodologies, however, are qualitative and prone to context bias. The current study demonstrated that microscopic inspection of the stain orientations provided a quantitative differentiation of bloodstains resulting from spatter versus contact transfer. Specifically, common knitted fabrics are comprised of parallel rows of left loop legs, in an upward diagonal orientation (/), and right loop legs in a downward diagonal orientation (\). The microscopic examination of more than 65,000 individual stained loop legs showed that spatter stains were approximately evenly distributed between left and right loop legs, but contact transfer stains were unevenly distributed. Depending on the type of surface contacted, as many as 82 percent of the stains were preferentially located on the left loop legs. The study further showed that in these fabrics the left loop legs protruded further out than the right loop legs by approximately 50 ìm, indicating that the observation of left loop legs preferentially stained over right loop legs was associated with the topography of the fabric. These findings suggest that microscopic quantification of the relative loop leg stain distributions could provide an objective means of differentiating contact transfer and spatter patterns in crime-scene reconstruction. (Publisher abstract modified)
Date Published: April 1, 2015