Maybe part of the thread problem is that we have a story with no real facts. But still I have to agree with PJ, some dumb teen tried to rob an off duty cop at gun point, the fact the cop was dressed as a clown is irrelevant because there is nothing wrong with a cop being dressed as a clown in a fund raiser.
In the process of the robbery the cop and robber struggled for possession of the robber's gun, then the robber got shot.
That seems to be the story from what we can see, but if there are other facts not covered in the initial story, then that may change our interpretation of the entire event.
Lacking further facts, we have to go on what we have at present. But still be slower to rush off onto final judgment.