Characterization of children's latent fingerprint residues by infrared microspectroscopy: forensic implications

The chemistry of children's latent fingerprint residues was investigated as a function of time and temperature by non-destructive spectrochemical analysis. Latent fingerprints from children, ranging in age from 2 to 11 years, were deposited onto aluminum-coated glass slides and were analyzed by Fourier-Transform Infrared Microspectroscopy. The results revealed that there are three major classes of compounds present in children's latent fingerprints: carboxylic acid salts, proteins, and esters. By studying the changes in the fingerprint residues as a function of time and at elevated temperatures, we discovered that the salts in the fingerprint residues are stable relative to the esters. These findings have relevant forensic implications; by targeting the acid salts instead of the esters or proteins, children's latent fingerprints may be recovered after extended periods of time have elapsed.