Dead on, Sorcha.

I was a cop once, in the Army, and I was even brought up on charges of police brutality. Yes, there was an investigation and even the drunk we had to fight to arrest agreed that we used no more force than necessary -- in fact, he was surprised we didn't use nightsticks. But I also knew a fellow cop who carried 50 round rounds of ammo (we were issued 5) because he really, really wanted to get in a shootout before he got out of the Army and another who got in "stick time" on a speeder (he was found to be mentally disturbed and should never have been assigned to the MPs).

Accountability, yes, without a doubt. But if you think the job is straightforward good vs. bad, try it sometime. Walk a mile in a cop's shoes: is this car you're stopping going to be the one with nut with gun in it? is this thug you're trying to handcuff the one with the hidden knife? will you see your family again?

My sympathies are with the victims, not the shooter.