Identification of gunshot residue from trace element by using ICP/OES identifikasi residu tembakan pistol daripada unsur surih menggunakan ICP/OES

The detection and identification of gunshot residue (GSR) may provide valuable investigative information to crimes involved with firearms discharge. These residues mainly composed of propellant residues, as well as metal components derived from primer mixtures, bullet, cartridge case and firearm itself. This study was carried out to observe the evidential value of metal elements which are lead (Pb), barium (Ba) and copper (Cu) in GSR detection by using inductively coupled plasma/optical emission spectrometry (ICP/OES). The shooting was performed by seven shooters; four male and three female in order to obtain GSR sample. Both hands of the shooters were swabbed based on three steps. The first step was obtaining GSR for washing before shooting, the second step was directly after shooting and the last step was washing after shooting. The result obtained using ICP-OES was successfully revealed that lead residue gives the highest concentration for the step of directly after shooting and washing hand after shooting followed by copper and barium. The study also shows that some of the residues discharged from the pistol were not only concentrated on the hand that grasped the pistol. The residues were detected with high concentration at opposite hand that grasped the pistol especially lead residues. These results showed that ICP/OES permits the determination of metals on hand of the shooter, and thus it will be very useful in assisting the police or forensic investigator when handled with crime associates with firearm.