“I was particularly struck by the extraordinary difficulty of proving a case against any one person on the train, and by the rather curious coincidence that in each case the testimony giving an alibi came from what I might describe as an ‘unlikely’ person. Thus, Mr. MacQueen and Colonel Arbuthnot provided alibis for each other—two persons between whom it seemed most unlikely there should have been any prior acquaintanceship. The same thing happened with the English valet and the Italian, and with the Swedish lady and the English girl. I said to myself: This is extraordinary—they cannot all be in it!
“And then, Messieurs, I saw light. They were all in it. For so many people connected with the Armstrong case to be travelling by the same train through coincidence was not only unlikely: it was impossible. It must be not chance, but design. I remembered a remark of Colonel Arbuthnot’s about trial by jury. A jury is composed of twelve people—there were twelve passengers—Ratchett was stabbed twelve times. And the thing that had worried me all along—the extraordinary crowd travelling in the Stamboul-Calais coach at a slack time of year—this was explained.
“Ratchett had escaped justice in America. There was no question as to his guilt. I visualised a self-appointed jury of twelve people who had condemned him to death and who by the exigencies of the case had themselves been forced to be his executioners. And immediately, on that assumption, the whole case fell into beautiful shining order.
“I saw it as a perfect mosaic, each person playing his or her allotted part. It was so arranged that, if suspicion should fall on any one person, the evidence of one or more of the others would clear the accused person and confuse the issue. Hardman’s evidence was necessary in case some outsider should be suspected of the crime and be unable to prove an alibi. The passengers in the Stamboul carriage were in no danger. Every minute detail of their evidence was worked out beforehand. The whole thing was a very cleverly planned jigsaw puzzle, so arranged that every fresh piece of knowledge that came to light made the solution of the whole more difficult. As my friend M. Bouc remarked, the case seemed fantastically impossible! That was exactly the impression intended to be conveyed.
“Did this solution explain everything? Yes, it did. The nature of the wounds—each inflicted by a different person. The artificial threatening letters—artificial since they were unreal, written only to be produced as evidence. (Doubtless there were real letters, warning Ratchett of his fate, which MacQueen destroyed, substituting for them these others.) Then Hardman’s story of being called in by Ratchett—a lie, of course, from beginning to end. The description of the mythical ‘small dark man with a womanish voice’—a convenient description since it had the merit of not incriminating any of the actual Wagon Lit conductors and would apply equally well to a man or a woman.
“The idea of stabbing is at first sight a curious one, but on reflection nothing else would fit the circumstances so well. A dagger was a weapon that could be used by everyone—strong or weak—and it made no noise. I fancy, though I may be wrong, that each person in turn entered Ratchett’s darkened compartment through that of Mrs. Hubbard—and struck! They themselves would never know which blow actually killed him.
“The final letter which Ratchett had probably found on his pillow was carefully burnt. With no clue pointing to the Armstrong case there would be absolutely no reason for suspecting any of the passengers on the train. It would be put down as an outside job, and the ‘small dark man with the womanish voice’ would actually have been seen by one or more of the passengers leaving the train, at Brod!
“I do not know exactly what happened when the conspirators discovered that this part of their plan was impossible owing to the accident to the train. There was, I imagine, a hasty consultation, and then they decided to go through with it. It was true that now one and all of the passengers were bound to come under suspicion, but that possibility had already been foreseen and provided for. The only additional thing to be done was to confuse the issue even further. Two so-called ‘clues’ were dropped in the dead man’s compartment—one incriminating Colonel Arbuthnot (who had the strongest alibi and whose connection with the Armstrong family was probably the hardest to prove); and the second clue, the handkerchief, incriminating Princess Dragomiroff who, by virtue of her social position, her particularly frail physique and the alibi given her by her maid and the conductor, was practically in an unassailable position.