Campus Sleuth (1948)

A photographer is choked to death just outside of where a college dance is being held. The body is discovered by Lee Watson (Warren Mills), but promptly disappears, as it is being whisked from one point to another on the campus by a night watchman who is an ex-convict. However, he is not the killer, and Freddie Trimball (Freddie Stewart), Betty Rogers (Noel Neill), Dodie Rogers (June Preisser), and Lee Watson set out to find the culprit, who managed to put a big damper on the Big Dance.