Dactyloscopy is the branch of forensics that deals with identifying individuals by analyzing the configurations of the friction ridges on the fingertips. The persistence and degradation of fingerprints depends on such factors as the individual's sex and BMI (body mass index) and the duration and conditions of their preservation. There is a great deal of information on how the passage of time affects the image of fingerprints composed of sebum and sweat, but little knowledge concerning the preservation of bloody fingerprints. The aim of the study was to determine the effect of sex, the state of the blood forming the print (dry vs. fresh), environmental factors (room vs. outdoor conditions), and time on the width of friction ridge impressions in fingerprints. Fingerprints made with fresh blood were found to persist longest, while prints left by women and exposed to outdoor conditions degraded most rapidly. The ambient temperature also had a significant effect on the width of friction ridge impressions and their degradation.
Keywords: bloody fingerprints; dactyloscopy; degradation; friction ridges; identification; print age.
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