I read an interview once with Mel Brooks where he said that he considered Harry Ritz, of the Ritz Brothers, the funniest of all comedians. The madcap comic energy he and his brothers, Al and Jimmy, bring to this fun 1939 riff on "old dark house" mysteries is certainly in line with what Mel Brooks would do years later with comedies like Young Frankenstein and Dracula: Dead and Loving It.
Directed by Allan Dwan with swift pacing, the film opens with a newspaper montage detailing a series of murders carried out by a killer known as The Gorilla. The killer has notified his next victim, a wealthy businessman (Lionel Atwill), of his impending doom. Atwill owes someone a great deal of money that he cannot pay, and then there's the matter of the forthcoming inheritance to be split between him and his niece (Anita Louise), so Atwill hires a trio of detectives (the Ritz Brothers) to protect him, who of course only add to the chaos. Things are further complicated when an actual escaped gorilla (actually Art Miles in a gorilla suit) shows up at the house, as well as a mysterious stranger (Joseph Calleia). Also on hand are Patsy Kelly as the zany maid and Bela Lugosi as the creepy butler.
The whole thing is a good deal of silly fun, especially if you enjoy these kind of haunted house mysteries, with lots of creaking doors, lights flickering on and off, and people disappearing into hidden passageways around the elaborate mansion set. The plot (based on an old play by Ralph Spence) is just straight enough to work on its own, and the added comic presence of the Ritz Brothers just cranks everything up a notch. Recommended for a good late night comedy.