I can understand a family member, or even a best-buddy taking revenge, on the person who killed their relative or buddy.  Revenge on only the person responsible.  But for someone to chose random targets, who were not involved in whatever grievance Du Jour, impresses me as just another murderer at heart, scapegoating whomever is handiest.  Had either of the officers, in Missouri or Georgia, been killed by family or friend of the ones they killed, I would have just figured it was Karma.  But some people just get an urge to kill, latching on to the flimsiest of excuses, and snap-shoot at the most convenient targets, and it isn't a matter of Karma at all.  It's just plain murder, by a vicious killer, a "mad-dog", who had no regard for another human being.  I could care less about whatever mental problems, or whichever psychotropic drug prescription that may have triggered him.  A "mad-dog" may not be responsible for getting bit by a rabid bat, but it still must be put down.