Who's Guilty? is a 1945 American film serial. It was the 28th of 57 serials released by Columbia Pictures. Who's Guilty? was a rare attempt at a whodunit mystery film in serial form. The serial's villain (The Voice) was designed to look like The Shadow on the poster. The film co-starred some well-known actors, such as Charles Middleton, Wheeler Oakman and Minerva Urecal. Robert Kent played the lead role of Detective Bob Stewart.

Walter Calvert (Clark) calls upon his brother Henry at his eerie old house and demands a share of the family fortune, threatening to kill Henry if he doesn't get it. Within days, Henry's car goes over a cliff. Bob Stewart (Kent), a detective Henry asked to investigate the matter if he should die, begins his investigation and Duke Ellis, a newspaper reporter friend, is with him. Bob meets the family at its mansion and questions Henry's sister, his half-brother, his nephew and his nephew's bride, along with Ruth Allen (Ward), whose father was in business with Henry. Henry's brother Patton (Middleton) and a shadowy figure known as The Voice plan to kill all the relatives and divide the fortune. As the murder attempts multiply, Bob, Ruth and Duke endeavor to track down the masterminds and bring them to justice.

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