I believe that there are crimes so terrible that execution is an issue to carried out and decided by the offended party, for instance someone who raped, tortured my 13 year old in way to ghastly and morbid to describe to anyone, yet alone me, the childs mother. I believe the sentence to be executed should be reviewed by a jury, and judge, and then metered out by the hand of the injured parties. If they can kill the individual the individual dies. If they do they live with there very core of being and maybe it will provide some comfort or maybe they will simply not do it. But it really is upto the people who have to live with knowing this monster breathes
Interesting question.