You're completely missing the point. The law of diminishing returns applies. These killers are already operating under severe penalties. They don't care how much more punishment is added to the penalty. They don't care one little bit what the damn penalties are! Most of them aren't to concerned when they destroy their own selves with hard drugs. If you think they do, then you're only being misled by the BS that flows after they're caught.
Criminals are made not born.