High cyanide level in a homicide victim burned after death: evidence of post-mortem diffusion

Elevated levels of carbon monoxide and cyanide serve as evidence of intravital burning in fire victims. Hydrogen cyanide is released by combustion of nitrogen-containing organic material such as plastics and wool. We present a case of a man who died of haemopneumothorax caused by a stab wound. According to several eye witnesses the body was wrapped in a plastic sheet and burned 2 days after death with the aid of gasoline. No coal pigment was observed in the mucosa of the upper airways at autopsy. The blood sample taken from the pulmonary vessels 6 days after death disclosed a level of blood carboxyhaemoglobin of 4% and of blood cyanide of 10 mg/l. The low carboxy-haemoglobin level was consistent with the smoking habits of the victim. The thoracic cavity had been opened by burning of the intercostal soft tissue. This allowed hydrogen cyanide gas to enter the thoracic cavity and diffuse into the blood probably causing the high blood-cyanide level.