I believe that human life is the greatest value on earth, Therefore I think that it is impossible to deprive a life of even a criminal. Each person should be given a chance to a second normal life and every chance should be fully received.
Criminals don't deserve a second chance, when the victims can't have one. Also, most of the hardened criminals can't be rehabilitated despite whatever the efforts the government and the authorities do.
Sad to say but I think you're right. Hardened criminals have more chance of committing more crimes that actually changing for the better. We may very well be killing off a lot of innocent people if men like these are left roaming because let's face it, if an evil person has deep connections in the government, it would be easy to bribe their way out. But justice has to be fair and meted to everyone