You can find the video online. He was acting crazy carrying what appeared to be a real gun, moving around in a manner that made it appear that he was prepared to use said gun. When police approached, and yelled at him, instead of dropping the gun he turned towards them, bringing the gun around towards them as well. This most likely was simply a result of him turning towards them, but any police officer faced with a situation where someone appearing to be carrying a semi-auto rifle turns the gun towards them is going to shoot them. It doesn't matter if they're black, white, or green. The bullets that might be flying at officers would kill them just the same, regardless of the color of the finger pulling the trigger.