Experiments on the DNA contamination risk via latent fingerprint brushes

One of the crucial tasks of a crime scene investigation is the search for latent fingerprints. The most common technique for the detection and development of latent fingerprints is the use of brushes with carbon black powder. As DNA analysis of latent fingerprints is already a common technique to obtain additional information, 51 used latent fingerprint brushes were analyzed to check if the brushes may be a source of DNA contamination. On 86% of the tested brushes, DNA could be observed in partial or full profiles, mostly as DNA mixtures. Following these pre-testing results, a secondary transfer study was carried out with used and artificially contaminated brushes. The typing results of these tests could prove a limited DNA contamination risk via latent fingerprint brushes via secondary transfer.