The Living Ghost
A detective investigating kidnapping case discovers the victim, who may be a zombie.
A screwball detective looks into a murder in a wealthy family. Goofy, fast-talking, 40's comedy that's fairly average.
One-Shot Beuadine did this Monogram cheapie horror/mystery in which a private eye must solve a kidnapping and discovers a mysterious figure is doing chemical lobotomies to create living zombies. Forgettable and dumb.