As human who can see what the criminals did, we want them to be put to death as punishment for their sins. We want to eliminate those wicked people so that they can no longer repeat such cruelty.  But God teaches us to love the sinners as much as we love ourselves. We should demonstrate the love that God gave us. We should give them a chance to change and to live a new life. In order to do this, we have to learn how to forgive and forget and leave it to the Lord. God is a just God. Do not put the justice into our hands. Let God do it.