Gunshot residue inserted under hair scales as a result of a muzzle blast

The victim was alleged to have been shot in the head with a .40 caliber pistol from several feet. The defendant claimed that the shot was on the order of inches. Examination in the scanning electron microscope of the hair from around the victim's wound showed no adherent gunshot residue (GSR). However, when the hair was pulled apart by the adhesive of a standard GSR sampler, GSR was found associated with the exposed inner surfaces of the cuticle and cortex fragments. The pistol was discharged close enough to the victim's head that some of the cuticular scales were lifted in the muzzle blast which allowed GSR to be inserted under those scales. Gunshot residue associated with the surface of the victim's hair had somehow been removed. The defendant's account of the shooting was verified by the presence of under-scale GSR.