April 21, 2022

Developing latent fingerprints using the traditional brush-and-powder method can be a time-consuming process, particularly at large crime scenes, and it has the potential to damage delicate fingerprint ridges when improper tools and techniques are used. The purpose of this study was to examine the viability of dispersing fluorescent starch powder through a sandblaster to develop latent fingerprints. Fingerprints (n=144) were deposited on six substrates and were developed at four time intervals. Under low pressure, the samples were fogged with commercial fluorescent yellow cornstarch powder dispersed through a sandblasting gun attachment on an air compressor. Excess powder was removed using compressed air, and the results were photographed and then preserved. Ninety-four percent of fingerprints (n=136) were developed. Eighty-six percent (n=124) of all fingerprints developed with sufficient detail for comparison to a known, and 76% (n=110) contained sufficient detail for identification. The fingerprint quality was strongly dependent on the substrate and the age of the fingerprint. The results were visible under natural light, but detail was further enhanced under 365 nm or 450 nm light, the latter coupled with an orange barrier filter. The results demonstrate that this novel powder application technique may hold potential as a viable method for processing large crime scenes in a timely, economical, efficient, contactless, and effective manner.