The main shooter in the Ayers killing was identified as Billy Shane Harrison who locals reported had just recently returned from a tour in Iraq after getting out of the military, presumably Army. Dude probably did not have any problem passing any shooting test thrown his way, but whether or not he had the use of force rules spelled out is another matter.

I got the strong impression from the reports that he was basically added to the narcotics team to be Chance Oxner's attack dog. Oxner was apparently pretty well known as a bad guy in that area. I seriously doubt either of those two would now be able to get a law enforcement job outside of their area. The "chatter" on cop forums was that those two were straight up fuckups. Only the cop groupie trolls in some mixed and open forums could even defend them, sort of like the idiots who would defend the cops involved in the LAPD Rampart scandal years ago.

Kinda hard for the cop groupies at lightfighter.com to defend the cops in the Rampart scandal when even Wikipedia articles point out that several are card carrying color flashing bloods gang members.