Criminal Investigator (movie, 1942)

A reporter investigates the murder of a showgirl, who was the widow of a millionaire. While digging in to the mysterious murder of a showgirl (Vivian Wilcox), intrepid reporter Bob Martin (Robert Lowery) uncovers a connection between that case and another one he's been working on. An inmate (Lawrence Creighton) holds the key to the crime, but there's one problem: He's deaf and mute. Meanwhile, the murderers (Jan Wiley and Charlie Hall) appear to be working for a very powerful person.