(Mystery) Dark Intruder - Leslie Nielsen, Peter Mark Richman, Judi Meredith 1965

https://www.imdb.com/title/tt0059083/ The story takes place in 1890 San Francisco, where a series of gruesome murders attracts the attention of Brett Kingsford (Leslie Nielsen), a playboy detective with a secret crime lab, a library of occult tomes, and an invaluable dwarf assistant (Charles Bolender).