Postscript-
I never could see how any Christians could support the death penalty, since, not only are you depriving somebody of extant life, you're depriving them of life in the hereafter. I mean, killing somebody is pretty much proscribed in the Ten Commandments. If you're going to ignore that, you'll also have to ignore the potential for the executee to find salvation through penance in his remaining time on Earth.
If a murderer doesn't repent before his execution, it doesn't mean he never would have. Therefore, the death penalty, in Christian eschatology, is simply an eternal torture sentence.