We’re taught that if we repent and ask for forgiveness we will be forgiven. So someone who rapes a child, sincerely repents and asks for forgiveness, will be forgiven. That’s God’s call and I accept it. My problem is I have to forgive the evil creep, too, or I won’t be forgiven. I just hope when I get to heaven I won’t know everyone else’s sin.
In the case of someone you don't know, believers understand that God will repay, and a felon's repentance towards God does not excuse him or her from appropriate civil penalties. It is the principle of "penitence" and "penetentiaries" based in the rule of law that keeps us from exacting cruel and unusual punishments or wreaking vengeance on a covict or his/her family for the sake of satisfying blood lust.