Scuba diving fatalities are rare and sometimes extremely difficult to explain. A thorough forensic investigation, conducted by a qualified team, helps avoid possible later questions and doubts, family concerns and judicial matters, since a significant body of evidence is lost after the body of the victim is buried or the equipment is reused. We report about a death of a scuba diver who was drowned while diving to the depth of 30 meters. Before being assisted to the surface, the diver panicked and removed the regulator from his mouth. The technical expertise of the scuba gear and the chemical analysis of the air from the high-pressure cylinder revealed no irregularities. Homicide, suicide, nitrogen narcosis, oxygen toxicity, and regulator malfunction were ruled out as possible causes of death. The most probable cause that triggered the event was vomiting into the regulator, as confirmed nearly 4 years later by the toxicological analysis of the traces of matter found in the dry chamber of the breathing regulator. Such an analysis should be considered when investigating suspicious diving related deaths and could be undertaken even after a significant time delay if the equipment is kept properly stored.