hahaha
but no way did doc huge murder him
impossible
He was there sitting taking pics of his best friend's rigor mortis body as the forensics carried him around. It's not normal behavior by what should be a grief stricken friend.
If he didn't kill him, but knew someone did, he wouldn't dare tell the cops that. I still think it's somewhat possible Leo had some extreme psychotic break due to drugs and somehow managed to kill himself, but this would be an extremely rare type of incident, a fluke.