The term “overkilling” in forensic medicine is not clearly defined and is used to refer to homicides involving unusually massive injuries, far exceeding those necessary to kill the victim. This is the clinical case of a dog found in February 2023 in a town near Naples, with a rope around its neck and the metacarpal region of its forelimbs. The dog was taken to the Istituto Zooprofilattico Sperimentale del Mezzogiorno (IZSM, Portici, Southern Italy), where it underwent a total body radiographic study performed using the “Philosophy HF400” X-ray device (Pan Vet, Kildare Town, Ireland). Subsequently, a full autopsy was performed, and samples of the injured organs were analyzed by accredited in-house laboratories for microbiological, histological and toxicological analyses. The autopsy revealed anatomopathological lesions compatible with strangulation, which were confirmed by histological examination. The autopsy also reported serosanguineous chest effusion, food material mixed with blackish microgranules and harmful substances in the stomach and, finally, uncoagulated blood in the atrioventricular chambers of the heart. These findings raised the suspicion of poisoning, which was confirmed by the positive outcome of toxicological tests.