by the two of them … Knighton and Ada Mason； working together。 Knighton was in Paris that day on your business。 He boarded the train somewhere on its way round the ceinture。 Mrs Kettering would be surprised； but she would be quite unsuspicious。 Perhaps he draws her attention to something out the window； and as she turns to look he slips the cord round her neck … and the whole thing is over in a second or two。 The door of the partment is locked； and he and Ada Mason set to work。 They strip off the dead woman's outer clothes。 Mason and Knighton roll the body up in a rug and put it on the seat in the adjoining partment amongst the bags and suitcases。 Knighton drops off the train； taking the jewel…case containing the rubies with him。 Since the crime is not supposed to have been mitted until nearly twelve hours later he is perfectly safe； and his evidence and the supposed Mrs Kettering's words to the conductor will provide a perfect alibi for his acplice。
〃At the Gare de Lyon Ada Mason gets a dinner basket； and shutting herself into the toilet partment she quickly changes into her mistress's clothes； adjusts two false bunches of auburn curls； and generally makes up to resemble her as closely as possible。 When the conductor es to make up the bed； she tells him the prepared story about having left her maid behind in Paris； and whilst he is making up the berth； she stands looking out of the window； so that her back is towards the corridor and people passing along there。 That w