If we're going to use our prisons for punishment only, then we need to admit that there is (almost) no coming back into society from them and just hold people for life. 

Clearly that should be a non-starter. We desperately need to start using our prison dollars to rehabilitate those how can be rehabilitated. We also need much closer post-release monitoring of former inmates, not to harass them but to help them succeed. Perhaps sentences could include a training requirement that must be met prior to release (GED or some such) in order to keep prisoners from just marking time and then getting out to no prospects.

That said, each person determines on their own if they can be a monster. clearly, Mr. Killian made that awful transition. At least his killing of innocent people is at an end.