Since Phynaz isn't replying to the substance of what you're saying, I'll reply here, noting that I partially agree and partially disagree with you. See below:
Nope! The person who did this is a criminal. Criminals get chased down and if they don't get shot resisting arrest they're arrested, tried, found guilty and put in prison.
Actually, the person in question is not a common criminal. Since he expressed a desire to kill police in retaliation for cases like Eric Garner and Freddie Grey, his actions are more akin to those of the Dallas shooter, which is to say, it was politically motivated terrorism. Or at least politically motivated violence. The danger with this sort of thing is that it encourages others to take similar action for similar reasons, and because it may - wrongly - cast a movement like BLM, who otherwise has legitimate grievances, as being associated with violent intent toward police. Under the circumstances, viewing this like he was some guy high on meth who shot a cop after robbing a convenience store isn't really doing justice to the importance of his conduct.
As opposed to people who shoot people who pose no threat to them but do so while wearing a police uniform. Those people get indicted, get a paid vacation, occasionally get wildly successful gofundme campaigns, and maybe if they're incredibly unlucky actually get tried.
I agree with you, that police are not prosecuted or convicted as often as they should be. I'm just not so sure that raising this point in this context does anything other than distract from the real issue here, which is that whatever our grievances against cops, violence against cops is clearly not the answer. I'm not saying you disagree with that or that you condone this because clearly you do not. I'm just saying that what one chooses to focus discussion on is a reflection of their priorities. So if, for example, one chooses to raise an issue that the police could maybe in theory have wrongfully shot someone else, and doing so only a few posts into the thread, without saying anything else, one may give the impression that this person would rather focus on cop bashing than addressing the conduct which is the subject of the thread, because that person knows this conduct is indefensible and they'd rather discuss something else.
So in summary, it's not that you're wrong about the police often not facing consequences when they should. And it isn't that there's no legitimate concern over a bystander. It's a question of emphasis and priorities.