Personally, I would support hanging them high instead of putting them in prison for life... except I do hold certain relevant beliefs about the future of humanity. I think there's a decent chance that before this century is out, us humans will have mastery over our brains (which may or may not be the same gooey brains we've always had), and I think it would be tragic if we put even a bad man to death instead of imprisoning him for several decades then fixing his brain when the technology comes along. If prisons become too costly for the rest of us to support or if it's going to take a lot longer for the tech, then mass cryogenic suspensions would be better than straight up executions, and for free people cryonics would be better than dying of old age... Of course if I thought humans will never gain mastery over the brain, then sure, why not have executions for those with life sentences, who ideally are those where "education" and rehabilitation are impossible due to the way their brains are?