At the time of the legendary funk and soul singer's death, it was reported that congestive heart failure was the cause of death of the 73-year old Godfather of Soul.

More than a dozen people have called for a new inquiry into the star's death in a major CNN investigation that alleges that he and his wife Adrienne Brown were murdered. Brown died following a short illness on Christmas Day 2006, however the doctor who signed his death certificate has expressed suspicion over the swiftness of Brown's deterioration, especially as he had improved the previous day.   

“He changed too fast,” Marvin Crawford says. “He was a patient I would never have predicted would have coded ... But he died that night, and I did raise that question: What went wrong in that room?” Crawford says a nurse told him drug residue was found in a tube helping Brown to breathe, and says “somebody perhaps could have given him an illicit substance that led to his death”.