I think no one can decide to take the life of other human being, but also i consider that is very expensive (no too much, but unfairy expensive) for the "good" people to mantain an useless individual living. I think that any kind of human punishment has to have the following 2 proposites: 1) Fix the path of the lossen ones, in order to bring them back to society. 2) Dissuade the bad persons to commit crimes. Revenge is not good because it usually doesn't help anyone and doesn't recover what have been lost. I think that any individual may like to use their remaining live to understand their error, embrace religion, or just enjoy little pleasures. So, maybe it's a good idea to use life imprisonment instead of capital punishment, but compel the criminal to work (inside of the jail if possible) for his own food and if he wants to work more some other allowed goods, like books. As far as I know, work is a good way to avoid returning to bad habits and to encourage bad persons to redeem themselves with the society, maybe not archiving freedom but forgiveness.