KC,
I want to share something with you. A young man, a senior in college, the same age as my oldest daughter recently went to a party and had a really good time. He is not only his parent's only child, but also his grandparent's only grandchild. Well on the way home he lost control of his car, went across the medium, hit a tree and his car went off like a bomb. Only a few body parts were left and he essentially disappeared. His funeral was probably the largest event I've ever known to happen at our church. A memorial service, as no body was present; but the place was packed. Many people throughout the community (lots of young people who didn't go to our church - and tons of adults as well). When my wife described this - it make me realize all the more how thoroughly blessed I am.
Let it go my friend. They are probably too scared to come back and it's not worth letting it eat you away.