I don't buy any of the conspiracy theories. I think its a...

I don't buy any of the conspiracy theories. I think its a combination of jurisdiction issues, indecision from leadership and confusion.
There are a lot of people here that seem to think hitting a moving target the size of a lawn bowls ball at 150 yrds is some easy feat?
I can tell you its not a simple as some would suggest.
Not to mention the fact that he would be well aware they were likely to shoot at him as soon as they could see him adds to the difficulty of the shot immensely. AR 15 is not a heavy calibre fire arm, 223 I think, and semi auto you need to make the first shot count if you are semi freehand.
If you want my opinion he was very close to pulling off a very difficult shot, whether that be by accident or design and I've been around people who I consider expert rifle shots.