Now I'm confused

PITTSBURGH -- In June, Pittsburgh police arrested one of their own after discovering a man on the city's South Side was grazed by a bullet from an off-duty police officer's gun.

The off duty cop had a BAC of .11, but was found "not guilty of aggravated assault, drunken driving and reckless endangerment" by the judge. I find that odd since a citizen would surely have been found guilty under the same circumstances, and there would probably be another charge for carrying a firearm while intoxicated.

The part where it gets really confusing is here:

"In this particular case, we had testimony that Mr. Abel was assaulted, there were witnesses that saw Mr. Abel assaulted, and it's his responsibility as a citizen and as a police officer to pursue that person who assaulted him," Hanlon said.

So he had a duty as a citizen to pursue an antagonist with a firearm while intoxicated? Good to know. Somehow I don't think the same rules apply to those without a badge.