Well, that's kinda messed up.

Oklahoma drugstore shooting stirs debate over self-defense, turns a pharmacist into folk hero - OKLAHOMA CITY (AP) — Confronted by two holdup men, pharmacist Jerome Ersland pulled a gun, shot one of them in the head and chased the other away. Then, in a scene recorded by the drugstore's security camera, he went behind the counter, got another gun, and pumped five more bullets into the wounded teenager as he lay on the floor.

I have no problem with him shooting the bad guy the first time. Even shooting him again when he was down would have been perfectly reasonable, provided he did it right away, in the proverbial 'heat of the moment'. But leaving the scene, coming back, and THEN shooting him? Not cool. Not only was the criminal no longer a threat to his life, there is no reasonable way he could have _believed_ that such a threat existed. That turns this from self-defense, into homicide. While it's highly unlikely that a jury will convict him, the DA still did the right thing in charging him.