Theological question

So I'm reading a Max Lucado book called "In the grip of grace" and there was this one part that Max (him and I are like best friends so we are on the first name basis) mentioned Jefferey Dauhmer... the man that killed like 17 people and ate them. This man did awful and brutal things to these people and during the trial showed absolutly no remorse. Then while he was on death row he became a "born again christian", a few months later an inmate killed him. So I'm reading this and I got really bothered by it. So here's where I just want anyones input. I to a degree can understand God's grace, and that God will completly forgive our sins when we repent, but what about God's justice? I fully believed growing up that there are consequences for our actions. I just don't know if I can see God's justice in this story. Or should I not even try too look for it b/c he was no worse a sinner than I am? I don't know if I am even making sense it is just something that I have been thinking about for a while now and just wanted peoples input. Thanks friends :)