Mrs. Hubbard

Mrs Caroline Hubbard is a passenger in Murder on the Orient Express who presents herself as an American widow. On the night of the murder she rings for the conductor and later claims the murderer was in her compartment, and she is the one who finds the murder weapon in her sponge bag. Poirot reveals that she is really the actress Linda Arden, mother of Sonia Armstrong and grandmother of Daisy Armstrong; she admits everything and offers to take responsibility as the mastermind of the killing.