UC Davis

In forensic investigations, when porous substances are submitted for analysis, either fingerprint or DNA analysis can be performed. The purpose of this study was to see if it is possible to perform both fingerprint and DNA analysis on the same piece of evidence and to determine the sequence of analysis that produces the best results. Studies have focused on what fingerprint methods affect DNA analysis but have yet to focus on how DNA analysis affects fingerprint enhancement quality. There are many methods to enhance the visibility of fingerprints on porous substances, but this study chose to use ninhydrin and 1,2-indanedione. In this study, three volunteers deposited their DNA and latent prints onto five different paper substrates (money, copy paper, cardboard, cardstock, and thermal paper). The samples then went through one of the following sequences of analysis: 1) fingerprint enhancement first with ninhydrin method, 2) fingerprint enhancement first with 1,2-indanedione method, 3) DNA analysis first and then fingerprint enhancement with ninhydrin method, and 4) DNA analysis first and then fingerprint enhancement with 1,2-indanedione. The results show that the DNA analysis process significantly decreased the fingerprint enhancement quality while the fingerprint enhancement process with either ninhydrin or 1,2-indandione methods does not significantly decrease the quality and quantity of DNA. These results are important because both fingerprint enhancement and DNA analysis can be performed on the same paper substrates.