Postmortem Artifacts Caused by Freshwater Crab Scavenging on Human Remains in Sri Lanka

Artifacts from aquatic animal scavenging can disfigure human remains, making identification difficult, obscuring or mimicking antemortem injuries, and destroying evidence. Although freshwater crabs are common scavengers in tropical freshwater, literature describing their effects on human remains is limited. This case series describes postmortem scavenging by the freshwater crabs Oziotelphusa ceylonensis and Ceylonthelphusa rugosa in Sri Lanka, highlighting their forensic significance. Three adult males who died in separate incidents of accidental drowning were recovered from shallow freshwater streams in Sri Lanka. Freshwater crabs were observed scavenging on the bodies at the scene or recovered with the bodies during autopsy. The lesions consisted of superficial soft-tissue defects on the eyelids, lips, nose, ears, neck, chest, feet, and external genitalia. The injuries lacked vital reaction and were oval, elongated, or irregular in shape with scalloped margins and crater-like appearances, exposing underlying subcutaneous tissues or muscles. Internal examinations were consistent with drowning. Collected crab specimens were morphologically identified as Oziotelphusa ceylonensis in 2 cases and Ceylonthelphusa rugosa in one case. Freshwater crabs can produce characteristic postmortem artifacts that may mask or mimic antemortem injuries. Recognition of these artifacts is important for expressing accurate medico-legal opinions in cases involving human remains recovered from freshwater environments.