When a gun is fired, the majority of gunshot residues are deposited on the shooter’s hands. But these
residues disappear through contact with surfaces or washing. Therefore, the maximum time frame to
find GSR on a suspect’s hands is 8 h. The mucus, inside of a nostril, forms a surface layer where they are
trapped foreign particles. In this way, mucus inside of a gunshot suspect’s nostrils could act like an
adhesive medium to stick on it gaseous particles from a gunshot. In this study, the presence of GSR in
nasal mucus and its residence time is examined. A new procedure for the sampling of possible gunshot
residue accumulated in the nasal mucus is designed. Samples are taken with cotton swabs moistened
with a solution of EDTA and, after an acid digestion, are analysed by graphite furnace atomic absorption
spectrometry. In addition, samples of hands are taken for comparison purposes. GSR recovery has been
successful. The concentration of GSR in nasal mucus is found to be lower than on the hands, but with a
longer residence time. Thus, it is possible to expand the sampling time of a suspect also, as nasal mucus
cannot be contaminated by handling weapons.