Prowler, The (1981)

In 1945 a World War 2 veteran returns home to Avalon Bay, New Jersey, to find his girlfriend broke up with him and is dating someone else. He decides to kill them on the graduation dance. 35 years later, at the first dance since the killings, the murderer is back and starts killing the party-goers. Meantime, sheriff George Fraser is on his annual fishing trip and has left the town to his deputy Mark London, who investigates the killings with his (almost) girlfriend, Pam McDonald.