[Quote]indicative of him being on his knees/sitting down with his hands up. He had no gunpowder on him, [/quote]

Yeah, if he was sitting, 

1. How did the cop shoot the top of his head and leave no residue.
2. Why didn't Dorian Johnson say that?

Why would Dorian Johnson, who was extremely close to the incident and witnessed every minute say anything but the truth, if as you say the truth convicts the cop?