The Forgotten Law (1922)

Margaret Jarnette discovers that her husband Victor has been cheating on her and confronts him. Outraged, Victor has his lawyer rewrite his will so that in the event of his death, his brother Richard will get custody of his daughter Muriel, and his wife won't. When Victor dies shortly afterward, Richard suspects that Margaret had murdered him and takes custody of Muriel. However, he soon begins to suspect that things may not be quite as cut-and-dried as he thought they were.