Lionel Atwill plays Jerome Breen which has a near perfect alibi because as he strangles people he talks to whomever is available immediately after the murder scene to set up his alibi. It seems that Breen is the city philanthropist that is also "deaf & dumb." A string of murders involving stock brokers is unsolved and Insp. Riley cannot solve the murders. A witness talks to Breen as he leaves his latest victim which leads to the murder trial of Breen. Problem is that the witness testifies that Breen talked to him but all the medical doctors that examine Breen testify that Breen cannot physically talk. So Breen is acquitted. Riley discovers a clue as to how Breen can be medically "deaf & dumb" but still talk and pays with his life for this discovery. The clue turns out to be a logical but unexpected one. So if you like puzzles then you will enjoy this film.