All He Remembered Was Her Hair

The boy who murdered the girl is bad, the victim who was murdered is innocent and the girl who saw it all is just a bystander, right? The boy will get his sentence, the victim will get her funeral, and the girl will go back to her life, right? The boy is just a troubled teenager, the victim was just unlucky, and the girl was just in the wrong place at the wrong time, right?
Wrong.