They obviously thought they were being attacked as the brother standing there said so. Can't imagine he was such a criminal Mastermind as to say that just to bolster their impending case.
The cop is very lucky indeed they had zero intention to harm him.
Maybe the cop discharged his weapon accidentally while drawing it. Who knows
The baying lynch mob on here needs to wait for the actual video of what happened before and after the suspiciously cut video (if it is ever released)