Explosive blast effects on latent fingerprints

People can be identified by fingerprints located on blast affected fragments recovered during the investigation of bombing scenes. We placed 4 aluminium plates (100 mm x 100 mm x 3 mm) and 2 steel plates (150 mm x 150 mm x 45 mm) with latent fingerprints on them at a distance of 0.25-1 m from a 0.7 kg charge of CompB, and the same number of plates also containing fingerprints at a distance of 0.125-0.5 m from a 0.09 kg explosive charge in a separate experiment. We found that the blast-affected fingerprints were detectable by the Cyanoacrylate Fuming Method and that the blast damage to the fingerprints complied with the scaling law. Damage to the fingerprints was greater on the light plates than on the heavy plates. The mechanism of damage is likely to be due to excessive blast pressure and heat.