I think that police, taken as a group, exhibit the same tendency of populations generally: there are about 3% who are trouble. 97% are 'the good ones'.
Beside Sergeant Arthur, there are five others from my department in Iraq right now. One sent back one week after he was home to stay. Tears in the eyes of a 6', 230lb Marine give you an indication of how difficult a job our troops are doing.
My Lieutenant was whacked in the head by an RPG that ricocheted around inside his HumVee after taking the fingers off the driver. He got knocked clean out: in typical self effacing humor he acknowledges that, had he been hit anywhere else, the blow would have been certainly fatal. He's stiil over there, a Lt Colonel directing the MP raids.
Be comforted: 97% of the guys in police uniform are 'the good ones'. Three percent give the rest a bad rap.