A preliminary investigation into the use of FTIR microscopy as a probe for the identification of bullet entrance holes and the distance of firing

Abstract 

FTIR spectroscopy has been found to be a valuable probe for the analysis of the distribution of organic components such as nitroglycerine in gunshot residues deposited on and around the bullet entrance hole of the clothing of the victim in short range firearm discharges. The method can be utilised for the detection and estimation of organic gunshot residues (OGSR) on the hands and clothing of the shooter. The method is specific and sensitive and is likely to be free from interference from, for example, environmental pollution. The method shows potential to be utilised as a suitable alternative to the widely used SEM-EDX analysis of the total contents of lead, barium and antimony present in the gunshot deposits around the bullet entrance hole. The method was tested in the laboratory and the results were validated by Gas Chromatography-Mass Spectrometry (GC-MS).

Keywords: Bullet entrance hole, Distance determination, FTIR, GC-MS spectra, Gunshot residue