Visualisation of latent fingerprints on non-porous object immersed in stagnant tap water using safranin-tinted Candida rugosa lipase reagent

Abstract

Waterways have been used for disposing evidence by perpetrators, especially during homicide, rendering difficulties for forensic fingerprint investigators since water may destruct the amino acid components of fingerprints. Although the use of small particle reagent for visualising the lipid components of a fingerprint has been suggested, its use has been associated with numerous human as well as environmental toxicities, and hence, must be reduced. Therefore, this present research that developed a new environmentally-friendly safranin-tinted Candida rugosa lipase reagent (i.e. Lipase-Glutaraldehyde-Safranin, Lip-GA-Saf) for visualising latent fingerprints on non-porous surface (aluminium foils) immersed for up to 4 weeks in stagnant tap water acquires forensic significance. Results revealed that the quality of latent fingerprints (Fingermark Quality Scale) developed using Lip-GA-SAF was statistically better in all the four different durations of immersion than that of using SPR (p<0.05). Declining quality of fingerprints over longer period of immersion was also observed for both the Lip-GA-SAF reagent and SPR developed fingerprints. Considering the better quality of fingerprints developed using Lip-GA-SAF reagent, its usefulness in forensic practical caseworks appears promising.