The autopsy does not absolve the cop of all responsibility in his death.
It says that evidence is not consistent with death by strangulation, and points towards underlying heart disease as the core mechanism. This underlying heart disease is most certainly exacerbated by the decreased oxygen intake and stress of the officer kneeling on his neck for 8 minutes.
A knee was also on his neck for > 2 minutes after he went unresponsive. That's valuable time where in-field treatment (BLS) could have been applied. It's also unlikely that continuing to restrict his oxygen intake after he'd gone responsive was helpful to him.
The cop's action and inaction substantially contributed to his death. His death is very unlikely to have occured without that cops intervention. Therefore, the officer still bears substantial responsibility.
Saying this absolves the cop is pretty silly. Almost as silly as burning down your own neighborhood to own the establishment.
Edit: Grammar
