A Vietnam veteran struggling with trauma is killing young women in St. Louis, and two detectives, Turk Cekovsky and Terry TenBroek, are investigating the crimes alongside the roommate of one of the victims, Debi Chaney. “Delirium” (1979) initially resembles films like “The Centerfold Girls” and “The Toolbox Murders,” but it develops in a surprising direction after its beginning. It’s best to go into this film know…