The video shows the boy at the park and he seems to be all by himself walking around pointing the gun at random things, its hard to find other people in the video since its snow covered and looks bitter cold.
I think the cop was way too quick to pull the trigger here, especially when you watch the video. They straight up pulled on the grass and right into the park, then he was shot within seconds.
Its sad that this cop seemed to have slipped through the cracks, but then again we have some very high level CEO's that lied on resumes before as well. I think its safe to say theres ALWAYS someone who can slip by on resumes, background checks, etc.
Its an unfortunate event, clearly needs to be investigated to the fullest. Although, this cop might get off on a lack of evidence since you can't see if the kid pulls a weapon out or not.