I hear you, and that's one side of the argument.
The other side would be there are a lot of people thinking he's 100% guilty of that double murder. I followed that trial very closely, and to be honest with you, considering all the evidence, I for one thought he was guilty. I was surprised with the not guilty verdict. There, I said it. I thought he should have been convicted based on all the evidence.
So imagine how many people in that prison were ticked off by this guy who got away with murder(s) because he could afford a hot shot lawyer, while everyone else had to serve life. And imagine this lawyer is now on his way to a successful appeal, and imagine how pissed off these people could be. And imagine 5-6 people feeling that way and wanting to do something about it. Maybe 1-2 of those people were prison guards who were willing to turn a blind eye. Who knows?
It would be impossible to kill a man that size with your bare hands and not leave physical evidence, on his person or in the room, especially a small room like a cell. He's a high profile prisoner in custody, authorities will immediately prepare for a wrongful death law suit, they will bring in highly experienced professional investigators to investigate the scene.
To them or the coroner signs of foul play will be obvious, there will be obvious signs of a struggle and marks on the body inconsistent with suicide, if he has been strangled, by someone, likely 3 or four people there will be bruises in places there shouldn't be.