Young couple goes on van tour of US, boy comes back with van - no girl

My wife (and I think others here) think that she was basically trying to finally break up with him. And of course, he couldn't handle that and took sort of the "If I can't have you no one can" approach.

But this sort of account (her being so sad and him being angry) match up with that sort of scenario. If it's what actually happened.
Makes sense. She breaks up with him and maybe even tells him he (since it was her van, right?) that he needs to take his stuff and go. Things escalate, and in the heat of passion either accidentally or intentionally she ends up dead. He takes off on foot, then decides, fork it, she can't use the van anymore, hitchhikes back to the van and drives home. Sad.