Hidden hands ended her life! Whose were they?

Richard Arlen is the convicted murderer and Adrienne Ames his sister who believes in his innocence. We see the murder and the framing set-up at the beginning of the film, so there’s no mystery for the audience to solve. Just the pleasure of watching an intricate cat-and-mouse game, with the murderer one step ahead of his pursuers until the final, tense confrontation.