Sonny Liston was found dead by his wife on January 5, 1971, but the date that appeared on his death certificate is December 30, 1970. This date is based on a police estimate, but since the police also ruled that his death was due to a heroin overdose and Liston’s autopsy showed no evidence of such an event, the date may also be suspect.
In addition, several things one would expect to find at the site of a heroin injection, such a tourniquet or similar to tie off with and a spoon to cook in, were absent from the scene of Liston’s death. Nor did Liston have any history of heroin use – and it’s hard to believe that he could have kept such a thing a secret, given his well-known love of drinking and partying to excess.
It is widely believed that his death was a result of a criminal hit, ordered by unknown underworld figures, and that the police investigation and its findings were a coverup.