I'm not a supporter of the death penalty. I think my #1 reason is that if someone is executed, and evidence later arises that the person was innocent, there is no prisoner still alive to release.
So what can they do, put flowers on the grave?
Why execute?Because it's cheaper? It's not. It takes more money to litigate an execution than to feed a prisoner for a lifetime. Because it deters? It doesn't work as a deterrent. Statistical evidence is not on the side of the argument from deterrence. Because the killer deserves it? Is execution better than death for the criminal? And if the criminal tortured the victim, should the criminal be tortured in turn? What if he's a rapist?