NCJ Number
114849
Journal
Journal of Forensic Identification Volume: 39 Issue: 1 Dated: (January/February 1989) Pages: 42-51
Date Published
1989
Length
10 pages
Annotation
Footwear impressions containing components sensitive to a potassium thiocyanate reagent (KSCN) and which have been deposited on unbleached kraft paper or manila paper can be substantially enhanced through the KSCN reagent, followed by laser illumination.
Abstract
The footwear impressions were deposited on the paper using two methods. In one method, a visibly dusty floor was dampened by misting water from a spray bottle; the donor walked across the damp floor and then stepped on the papers. In the second method, papers were wetted and allowed to dry partially. Impressions were deposited by walking across a dry, visibly dirty floor and stepping on the paper. The reagent was applied as a fine mist and reacted with iron and other metal salts in the deposit to form a colored product. Laser excitation was accomplished with a 10 W copper vapor laser, using the 510 nm line at approximately 7 W output. The footwear marks were first examined using oblique incandescent lighting to photographically enhance the marks without KSCN chemical enhancement. The paper was next viewed under oblique laser illumination prior to spraying with the visualization agent to observe any enhancement that might occur from oblique laser illumination or from inherent luminescence suppression. The paper was next sprayed with the KSCN visualization reagent and allowed to dry. Finally, the papers were re-examined under laser illumination. 8 figures, 2 tables, 7 references.