Pathological Changes and Sodium Rhodizonate Test as Tools for Investigating Gunshot Wounds in Veterinary Forensic Pathology

Abstract

Gunshot wound morphology and gunshot residues (GSRs) evaluation have been poorly investigated in veterinary forensic pathology. The aims of the present study were to assess the gunshot wound morphology in animals and evaluate the detectability of lead deriving from GSRs using colorimetric techniques. To these aims, cadavers were divided into four different groups. Group A comprised eight animals who died from firearm-related injuries, while groups B and C included dog limbs shot using different shooting ranges; group D comprised dog limbs stabbed with a screwdriver. Morphological analysis was performed on all entry gunshot wounds. Lead residues were investigated using a Bullet Hole Testing Kit (BTK) and Rhodizonate Sodium histochemical staining (NaR-s). Gunshot wounds in group A showed an abrasion ring associated with hemorrhages and tissue necrosis. Groups B and C showed injuries related to the shooting range. NaR-s showed positive results in both animals that died from gunshot wounds and experimentally shot limbs. However, the number of positive cases and the pattern of lead distribution varied with the shooting range. Positive results by BTK were limited to close-contact shots in group B limbs. Our results suggest that both pathological examination and NaR tests represent valid tools for investigating gunshot wounds in veterinary pathology.

Keywords: forensic science; gunshot residues; penetrating injuries; veterinary forensic pathology.

Figure 1

Representative pathological and ballistic findings in group A cadavers; dog: (A) gunshot wound (B) subcutaneous hemorrhages around the entrance gunshot wound (C) ballistic material detected during the necropsy; bovine: (D) gunshot wound (E) subcutaneous hemorrhages around the entrance gunshot wound (F) ballistic material detected during the necropsy; horse: (G) gunshot wound (H) subcutaneous hemorrhages around the entrance gunshot wound (I) ballistic material detected during the necropsy.

Figure 2

Representative morphological alterations in group B limbs; close contact shot: (A) full metal jacket (B) copper-plated; 1 m shot: (C) full metal jacket (D) copper-plated; 6 m shot: (E) full metal jacket (F) copper-plated.

Figure 3

Graphical representation. (A): group A gunshot wound showing a circular morphology with irregular and hemorrhagic edges; (B): close contact shot in group B limbs showing an abrasion ring associated with a moderate amount of visible black material on the surface of the skin; (C): 1 and 6 m shots in group B limbs showing an abrasion ring without macroscopically visible signs of soot deposits.

Figure 4

Representative morphological alterations in group C limbs; 6 m (A) and 12 m shots (B).

Figure 5

Representative morphological alterations in group D limbs.

Figure 6

Bullet hole testing kit; Pistol: close contact shot (A,B) showing a pattern of lead distribution mimicking the shape of the entry wound in both (A) full metal jacket and (B) copper-plated cases; 1 m shot (C,D) and 6 m shot (E,F) showing negative results. Rifle: 6 m (G) and 12 m (H) shots showing negative results.

Figure 7

Representative skin morphological alterations in group A cadavers: (A,B) coagulative necrosis, hemorrhages and foreign material around the edges of the dog (A) and bovine (B) gunshot wounds (Hematoxylin and eosin Stain, original magnification 20×); (C,D) amorphous aggregates stained pink–brown with sodium rhodizonate in both dog (C) and bovine (D) gunshot wounds (NaR, original magnification 20%). (E,F) amorphous aggregates stained blue-violet with hydrochloric acid in dog (E) and bovine (F) gunshot wounds (NaR HCL 5%, original magnification 20%).

Figure 8

Representative skin morphological alterations in group B limbs: (A) close contact shot showing extensive protein agglutination and a moderate number of black deposits around the edges of the wound (arrow and insert); (B) intermediate shot range showing fragments of hair in deep dermis (arrowhead) and black deposits (arrow and insert) (Hematoxylin and eosin Stain, original magnification 30×). (C,D) close contact shot showing sodium rhodizonate positive deposits strongly clustered along the edges of the wound; (E,F) intermediate-range shot showing dotted positive aggregates (arrows) (NaR-s and NaR HCL 5%, original magnification 30×).

Figure 9

Number of positive cases and pattern of lead distribution for each assessed firearm (pistol and rifle), bullet (copper-plated, full metal jacket, and shotgun slug), and shooting ranges (close contact; intermediate and long-range).

Figure 10

NaR-s and NaR HCL 5% in group C limbs: (A,B): long-range shot showing scattered positive aggregates (NaR-s and NaR HCL 5%, original magnification 20×).

Figure 11

Representative skin morphological alterations in group D limbs: (A) moderate number of black deposits around the edges of the wound (arrows); absence of positive deposits (B) (original magnification 30×).