Given that I believe in reincarnation and karma, execution in this case would help balance the karma rather than putting it off until a future life.Let's try a scenerio:
Suppose you have a man who has raped and killed multiple children before being caught and tried. Suppose also that this animal has publicly stated that if given the chance he would gladly rape and kill another child. Now, firstly, why would any rational human being have a problem with removing this man from the face of the earth? Secondly, wouldn't a life sentence with no possibility of parole would be a long term death sentence anyway?
Religiously, Jesus never tried to stop the death sentences of the other two beside him on the crosses.
But given the way the criminal justice system works and the number of innocent people who are convicted of crimes, I'd want a higher standard of proof before a sentence of death. Perhaps "incontrovertible evidence".