I’m against the death penalty, but I am for life imprisonment without parole as an acceptable alternative. There are some who will always be dangerous to society.
The problem with “life imprisonment” is that (1) there’s always a chance a judge will release them, regardless of the original sentence, and (2) they can still harm others while in prison. On the other hand, a BIG problem with execution is that the person may not be guilty, and another is the possibility that a person may repent and be converted.
This is why I say it’s not an easy question.