NCJ Number
223057
Journal
Journal of Forensic Identification Volume: 58 Issue: 3 Dated: May/June 2008 Pages: 355-389
Date Published
May 2008
Length
35 pages
Annotation
This study examined distortions present in bloody fingermarks.
Abstract
Examiners constantly observe distortions in fingermarks and infer the causes of the distortion. This research drew conclusions from the experimental trials and proposed theoretical mechanisms for the production of tonally reversed fingermarks in blood. It also determined that video through glass or high-speed video might be an effective way to study the deposition process for bloody fingermarks and other relevant matrices. The research trials indicate that the currently accepted mechanism for the creation of a tonally reversed bloody impression is false. Tonally reversed bloody impressions were created through one of two proposed mechanisms: removal of excess blood preferentially from the ridges, followed by significant deposition pressure, or waiting a significant amount of time to allow blood on the ridges to dry, while leaving blood trapped and protected in the furrows still wet. In general, there is a need for systematic study of distortion mechanisms and the resulting appearance of ridge detail. To date, no experiments have been published measuring the cause and effect relationship of various deposition factors and the resultant appearance of the ridge detail in a bloody friction ridge impression. This study reports the effects of deposition pressure at four categories of pressure, the effects of increasing volumes of human blood loaded onto a finger, the effects of depositing impression on a horizontal surface versus a vertical surface, and the effects of allowing the blood to dry on the finger for a significant amount of time before depositing the impression. Tables, figures, references, and photographs