The Prowler

In 1945, a returning WWII vet gets a "Dear John" letter from his girlfriend telling him that she just can't wait any longer for him to come home.  Instead of doing what any sane person would do - namely moving on with your life and forgetting about such a hurtful bitch - he stalks her and her new man at a graduation dance.  When they decide that the dance is too dead for their tastes, they slip out and go visit a lover's point to get a little action on.  While the couple is starting to get hot and heavy, the vet makes his move and impales them on the business end of his pitchfork, leaving a single rose in the hand of his ex.  The crime is never solved, and no graduation dances were ever held on the same location again... Not until 1980, that is, when it's time for a new graduation dance.