A series of killings at a British circus prompts a Scotland Yard detective to launch an inquiry. Joan Crawford portrays the detached owner, with Ty Hardin as a tightrope walker, Diana Dors in a seductive role, and Judy Geeson as the proprietor’s daughter. “Berserk!” (1967) shares elements with “Circus of Horrors” (1960), but benefits from Crawford's presence; while I don’t particularly like her films, she undeniab…