Was that the first or second autopsy?
It was the first one released to the public. That was the one that was carried out by the independent examiner. Funny thing is though, the one carried out by the state medical examiner (the second one released) also stated that the cause of death was homicide related. It just also said that there were drugs in his system and the homicide probably wasn't intended.
The first autopsy found death likely by asphyxiation from one police officer putting pressure on his throat. The other autopsy found death by cardiopulmonary arrest due to one police officer putting pressure on the throat and another putting pressure on the chest preventing the heart from getting enough blood and oxygen.
That hasn't stopped people from claiming that the medical examiners autopsy cleared the police. It didn't. It just means that instead of one being charged with murder, it's actually two officers.