Tandem bullet injury: an unusual variant of an unusual injury

A 41-year old male sustained a fatal gunshot wound during a house robbery. Police enquiries and scene investigation revealed that a single shot had been fired and that one spent 9 mm cartridge case was retrieved from the scene. At autopsy the beige short sleeved jacket and printed white T-shirt worn by the deceased each displayed a single perforating defect on the right front aspect (approximately overlying the pectoral region), with associated blood staining (Fig. 1). Two penetrating wounds were present on the skin of the anterior aspect of the right pectoral region, one above the other and in close proximity to each other, located approximately 6 cm medial to the right nipple (Fig. 2). The uppermost wound was round in shape, measuring 0.9 cm in diameter with a distinct but irregular concentric peripheral collar of abrasion. The lowermost wound was oval in shape, measuring 2 9 1 cm in size and with a relatively ‘‘clean cut’’ appearance of the edges, except in the 9 o’clock to 1 o’clock position, where there was irregular superficial abrasion of the adjacent skin. Neither of the wounds displayed features of associated heat injury, soot deposition or powder tattooing. Upon palpation and superficial dissection of the back, at a point 25 cm below the level of the shoulder and 5 cm medial to the midline on the left, a somewhat misshapen 7.65 mm projectile was recovered. Transillumination (C-arm fluoroscopy) revealed the presence of two further foreign metal objects in the chest region; one had the typical appearance of a heavy caliber handgun projectile (left posterior chest wall), while the other had the appearance of a spent (misshapen) cartridge case, in the right chest cavity (Fig. 3). Upon opening of the chest, a free-lying deformed 7.65 mm cartridge case was recovered from the right pleural cavity, with bilateral hemothoraces. There were two penetrating wound tracts traversing the right anterior chest wall between the third and fourth ribs parasternally (with some fragmentation of the adjacent sternum) and with two slightly divergent wound tracts subsequently perforating the chest cavity from front to back and from right to left. One tract tangentially involved (inter alia) the anteromedial portion of the upper lobe of the right lung, the proximal ascending aorta and the posteromedial portion of the lower lobe of the left lung, culminating where the spent 7.65 mm caliber projectile had been removed from the superficial subcutaneous tissues of the back (as described above). The second wound tract traversed the anterior pericardial sac, the right and left atria of the heart and the posteromedial portion of the lower lobe of the left lung, culminating in the eighth intercostal space (posterior), where a spent 9 mm caliber projectile was found. Interestingly, the front end of the latter projectile had a clearly visible indentation, being a mirror imprint which corresponded to the base of the cartridge case of the 7.65 mm projectile (Figs. 4, 5). Based on the overall findings, we postulate that the intact 7.65 mm round had previously lodged within the barrel of the firearm, where it was subsequently impacted from behind by the fired 9 mm round and with all the projectiles then entering the chest of the deceased. The approximate configuration of the projectiles would then have been as displayed in the reconstructed sequence shown in Fig. 6. It is not certain which of the wounds was caused by which of the projectiles, but it seems likely that the larger, ovoid wound may have been caused by the 7.65 mm cartridge and/or projectile, with the 9 mm L. du Toit-Prinsloo (&) N. K. Morris G. Saayman Department of Forensic Medicine, University of Pretoria, Private Bag X323, Arcadia 0007, South Africa e-mail: lorraine.dutoit@up.ac.za