Abstract The forensic information of criminal interest that can be obtained from a decomposing human corpse can be harmed by postmortem changes. The presence of the water beetle Rhantus validus feeding on a corpse found in an artificial freshwater pond in Peñehue, Región de La Araucanía, Chile, and postmortem artifacts caused by their necrophagous activity is reported. These skin modifications can be confused with antemortem injuries. The ecological conditions that allow this feeding behavior and the forensic repercussions of this finding are discussed.