The Ninth Guest (1934).

Before Christie's And Then There Were None, penthouse partygoers in The Ninth Guest are informed by radio broadcast that they will be murdered one by one. The film is based on a play by Owen Davis and the novel The Invisible Host by Bruce Manning and Gwen Bristow. According to the 15 Feb. 1934 New York Sun, "Manning was on the [New Orleans Times] Picayune and Miss Bristow was on the Item. They both were assigned to cover a hanging in St. Mary's parish. There they were married—in the courthouse basement by a blind justice of the peace." (The Sun has swapped the papers—Bristow wrote for the Picayune and Manning for the Item.) Manning also was a screenwriter and director who worked on some film projects with Vera Caspary and Deanna Durbin, and Bristow is known for her Plantation trilogy.