Consider this. If a murderer is executed the expense is over. If a murderer not executed is released for any reason and murders again should not that cost be added to the non-death penalty side.
They should never be released. A life sentence should be a life sentence. I'll never agree with us killing a criminal once he/she is incarcerated and does not pose a further threat. A lot of these criminals were raised in poor environments, give them the rest of their life to undo the damage caused in their youth to find God and repent.