People being arrested frequently complain. Only the cop with the knee on his neck would know how much pressure he is putting. How do you know he pressed down harder after he said he couldn't breathe? Also, the autopsy said he didn't die of asphyxiation, so he obviously could still breathe. That doesn't excuse the cop. I think he killed the man by being reckless, and had no justification to hold him down for so long, but it doesn't mean he meant to kill him. 3rd degree murder is the right charge.