Look Football I just don't agree. If there is irrefutable proof, say video footage of one of these gunmen taking someone's life he should be killed. Why put someone in prison who you have no intention of rehabilitating? If you take someone's life you should lose yours.
Let's not have a stupid discussion on what constitutes proof and how 'innocent' people are put to death. I've said 'irrefutable proof', video evidence etc.
As for your friend being involved in hangings, well I say pay the people who have to do it even just 25% of what it would cost to incarcerate these people for life and you'll have plenty of volonteers. It's not a nice job but that doesn't mean it shouldn't be done.