Officer mistakenly shoots defender
Story here. The mistake seems understandable: officers respond to "shots fired," encounter a woman and children fleeing a home who report an armed man inside, announce and enter, encounter an armed man coming down the hall. Unfortunately, he was the homeowner; he was apparently coming back from subduing the perp, and either didn't hear the announcement, or under the stress didn't think to put down his gun.
It does put me in mind of a thought Prof. Bob Cottrol had, which was that most of the LE training targets he'd seen with sketches of people on them involved clearly good guys or clearly bad guys. Bad guys are snarling and trying to bring a gun to bear on you, etc.. Perhaps, he thought, it'd be good to have some ambiguous targets, armed man but not trying to bring gun to bear, etc., just to train for situations where shoot/no shoot is ambiguous.
Hat tip to reader William Taggart