NCJ Number
73712
Journal
Assets Protection Volume: 4 Issue: 5 Dated: (December 1979) Pages: 38-41,46-47
Date Published
1979
Length
6 pages
Annotation
Techniques for locating, preserving, transporting, and processing latent prints for use in criminal investigations are discussed.
Abstract
Generally, two techniques are used to locate latent prints on nonporous surfaces -- lights and fingerprint powders. Flat, smooth, or shiny surfaces are best examined with lights, while rounded or bumpy surfaces require powders. Despite problems in their use, powders are most popular because of their apparently long shelf life, low cost, varied application devices, and their ability to enhance latent visibility and allow latents to be lifted. Powders may be applied with camel hair, fiberglass, or magnetic brushes and with feather dusters, cotton, atomizers, or smokes. Powder effectiveness is affected by latent substances, age of the print, the surface bearing the print, environmental conditions, and the type of powder being used. The preferred method for locating latents on porous surfaces is iodine fuming. Once located, prints may be photographed and sent on to a lab for further processing, or a small portion of the item may be sent to the lab. Latent prints must be preserved, and information about their identification must be recorded through photographs, sketches, or notes. Latents may be lifted by using clear cellophane tape, frosted and trasnslucent plastic tape, plastic pieces and sheets, rubber or opaque lifters, or casting material. Transporting porous material with latents poses no real problems. However, it is best to process latents on nonporous material at the scene. Of the three types of chemical processes (iodine fuming, ninhydrin, and silver nitrate), iodine fuming is the cheapest, most versatile, easiest to apply, and no more hazardous to health than the other solutions. Sources of fingerprint supplies in the United States, Japan, Germany, Netherlands, and England are provided, as are 25 references.