Identification of geographic and cultural ancestry through chemical analysis of latent fingerprint residues

Abstract

The permanence and uniqueness of fingerprints and the analysis of physical characteristics associated with fingerprints have allowed for the identification of individuals in forensic investigations. However, there is additional information that may be obtained from latent fingerprints. Fingerprint residues are comprised of chemical components - those which are created and secreted from the body naturally (endogenous) and those from products outside the body that are ingested or applied on the skin (exogeneous) - that have previously been used by researchers to identify an individual's age, gender, and even lifestyle. This information may be useful for the inclusion and exclusion of suspects when physical fingerprint characteristics may be unidentifiable or may be a means of adding additional information to preexisting physical characteristic analyses. However, there is currently no scientific literature regarding the ability to identify an individual's geographic and cultural ancestry through analysis of latent fingerprint residues. The purpose of this study was to identify a chemical pattern which might allow investigators to identify an individual's geographic and cultural ancestry through the analysis of latent fingerprint residues using Mass Spectrometry - specifically Desorption Electrospray Ionization - Mass Spectrometry - as a medium for analysis. Individuals from varying racial backgrounds (Hispanic, Asian, European, African, and Middle Eastern) were asked to deposit a single right index print onto a piece of Mylar film. Following collection of prints, samples were analyzed using the DESI Synapt G2 instrument. Results of the study indicated that identification of geographic and cultural ancestry based on latent fingerprint residues may be possible, but further study is needed. In most cases, it was seen that an individual has significant agreement of chemical residues within their fingerprints. However, for individuals of the same or even different geographic and cultural ancestries, there is less definitive results as to if the chemistry of their latent print residues are similar or significantly different. In total, no distinct observations can be made from the data obtained, and further investigation is required to establish any relationships between geographic and cultural ancestries and the chemistry of fingerprint residues.