Recovery of Latent Fingerprints after Immersion in Various Aquatic Conditions

Abstract

As the use of waterways continues to increase for recreational purposes, so do the incidents of criminals using waterways to dispose of evidence. Although some may believe that items recovered underwater will have no forensic value, this research shows that identifiable fingerprints may still be recovered. An experiment was conducted to establish the value of latent fingerprint evidence that had been submerged in a natural aquatic environment. The two factors analyzed in this study that affect the deterioration rate of latent fingerprints were stream current and length of time submerged. To evaluate these factors, latent fingerprints were deposited on metallic objects simulating the substrate of a knife or gun and submerged in a freshwater stream at locations subject to various powers of current for 24, 48, and 72 hours. After recovery, the items were subjected to cyanoacrylate fuming followed by black powder processing; the prints were lifted with tape and examined. Each print was evaluated for its individualizing power based on a scoring system. Latent fingerprints subjected to higher current velocity were significantly more deteriorated than prints subjected to little to no current. A decrease in latent fingerprint visualization with longer periods of submersion was also observed. The results of this study demonstrate the importance of understanding the interactions between latent fingerprints and the various factors of the natural aquatic environment to better aid in criminal investigations and potentially linking evidence to a perpetrator.