Punishment must fit the crime. To me the biggest challenge I can think of is, "Love your enemies, and do good to those who persecute you." Of course that does not mean that crimes should go unpunished. It does mean that you should not harbour hatred of a bike thief and shoot them if possible.
We should consider the social system that produce such cases - the only difference between me and them is providence - an accident, if you will, of where and to what parents one was born.
Despite what i said earlier, I have to admit Jur is correct.