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Developing DNA Friendly Fluorogenic Methods for Detecting, Enhancing, and Preserving Bloody and Proteinaceous Impression Evidence

NCJ Number
Date Published
May 2016
79 pages

This project's goal was to optimize the detection, enhancement, and preservation of impressions made in blood, semen, saliva, eccrine/sebaceous sweat, and non-human oil using Zar-Pro fluorescent blood lifters and three novel fluorogenic enhancement sprays, so as to preserve DNA in biological material in which the impressions are set.


The study found that amplifiable DNA capable of producing full STR profiles can be extracted from Zar-Pro lifted semen and blood impressions, but not from impressions in any biofluid treated with the fluorogenic enhancement sprays. Thus, in simplifying the collection and preservation of impression evidence, while expanding the usefulness of enhancement methods to include DNA friendly approaches, both impression evidence and DNA can be recovered from a single evidentiary item. Based on preliminary results, the enhanced impressions remain fluorescent and can be preserved long-term. In the effort to create DNA friendly fluorogenic enhancement methods, DNA extraction, amplification, and analysis was conducted on each of the enhancement methods used in the project. The degree of stability afforded impressions enhanced with the novel dye stain sprays has yet to be determined; however, the Zar-Pro lifters are durable, with previous studies demonstrating they have the ability to preserve lifted impressions in a manner similar to a photograph with long-lasting fluorogenic properties. Future research projects will evaluate the quality of the ridge detail and fluorescence intensity of the preserved sample sets, so as to better address the issues pertaining to preservation. The research methodology is described in detail. 103 figures, 11 tables, and 69 references

Date Published: May 1, 2016