The Scarlet Clue
Government agent Charlie Chan is investigating a spy ring intent on stealing radar plans, which leads him to a radio station in a building also containing a radar research facility. Stars: Sidney Toler, Mantan Moreland, Ben Carter, and Benson Fong Mantan Moreland and Ben Carter perform a version of their nightclub routine. A lack of a copyright notice in the film puts it in the public domain. IMDb Link