When killer cops walk

After being tasered seven times, US Marine Hale was shot point blank in the chest three times by police Lt. William Browne:

Browne claimed self-defense. But Hale was no threat to anyone when he was killed. He didn't resist arrest. He had no weapon.

More detailed account here.
You have to wonder what kinds of individuals become constables. If you remember the Stanford Prison Experiment that induced "normal" students to become cruel when cued as guards, consider this revisit of the volunteering process -- you can guess what happened:

Carnahan and McFarland ... re-ran the volunteering part of the study to see what sort of people would volunteer for a two week study ‘of prison life’, compared to those volunteering for a study described in an identical manner but with the ‘prison life’ bit taken out.