Examination of Firearm

Firearms need to be examined by other experts for evidence of misfiring (212). There may be a need to reconcile an apparent discrepancy among the autopsy, scene findings, and circumstances of the death (58,130). Fingerprints of the deceased may be seen on the cartridge or firearm (60,101,105). In one study, fingerprints were found on the gun in 12% of cases (106).

The presence of blood from the victim on or in the barrel of the weapon assists in the determination of range. The injection of propellant and gases at close range into the

Fig. 50. Intracranial bullet ricochet. Same case as Fig. 49. Formalin-fixed brain. (A) Wound track to left and forward relative to deceased (exit—arrow). Coronal slice of brain. (B) Bulging fracture (F) on cranium marking exit from left cerebral hemisphere. (C) Superficial path ("gutter"; white arrows) along surface of brain from exit (black arrow) to recovery site of bullet (arrowhead).

Fig. 50. Intracranial bullet ricochet. Same case as Fig. 49. Formalin-fixed brain. (A) Wound track to left and forward relative to deceased (exit—arrow). Coronal slice of brain. (B) Bulging fracture (F) on cranium marking exit from left cerebral hemisphere. (C) Superficial path ("gutter"; white arrows) along surface of brain from exit (black arrow) to recovery site of bullet (arrowhead).

body, followed by closure of the temporary cavity, leads to backspatter, i.e., retrograde expulsion of blood and tissue aerosol, bone, and bullet particles from the wound (95,155,213,214). The finding of backspatter on the hand determines whether the victim actually fired the firearm (see Heading 13. and ref. 213). DNA analysis, if necessary, can confirm the link. Backspatter occurs frequently with close-range shots, but its absence does not necessarily indicate an intermediate or distant wound (213). Spatter on a weapon can be detected even if the weapon is fired again (63).

The following was found in one study conducted at the Office of the Medical Examiner in Dallas County, TX (63):

Fig. 51. Multishot suicide (see Fig. 24). (A) Subarachnoid hemorrhage of frontal lobe (arrow) owing to tangential self-inflicted wound of forehead. Cranium was not penetrated. (B) Coronal slice of section of formalin-fixed brain showing corresponding "coup" contusion.

Incidence of blood (as detected by leuchomalachite green) Revolvers/pistols/rifles Shotguns

Inside barrel About one-halfa About three quarters

Outside barrel About three-quartersb About 85%b aPositive result consistent with barrel within 7.5 cm (3 in.) of surface. bBlood deposited up to several feet (about 1 m) away on the barrels of long guns.

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