Microscopic and spectroscopic features of gunpowder and its documentation in gunshot wounds in charred bodies.

Determining the direction and range of fire of gunshot wounds in charred bodies can be difficult because soot resulting from thermal injury can grossly be identical to soot arising from a contact or close-range firearm discharge. Two charred bodies had gunshot wounds of the head and neck region that were distorted by thermal effect, precluding determination of the direction and range of fire by gross findings alone. By microscopy, deep wound tissue from each charred body had foreign material suggestive of gunpowder. Samples of the foreign material were examined by Fourier transform infrared (FT-IR) microscopy and determined to be cellulose nitrate (nitrocellulose), a main component of gunpowder. In addition, 12 cases of suicide in well-preserved bodies with contact gunshot wounds were examined with FT-IR microscopy, confirming the presence of cellulose nitrate in 6 (50%) of the cases. Identification of cellulose nitrate in the tracks of gunshot wounds can assist in the determination of direction and range of fire when the surface features are charred.