“Not at all! The letters were sent to me because the essence of your plan was that one of them should be wrongly addressed and go astray—but you cannot arrange for a letter addressed to the Criminal Investigation Department of Scotland Yard to go astray! It is necessary to have a private address. You chose me as a fairly well-known person, and a person who was sure to take the letters to the police—and also, in your rather insular mind, you enjoyed scoring off a foreigner.
“You addressed your envelope very cleverly—Whitehaven—Whitehorse—quite a natural slip. Only Hastings was sufficiently perspicacious to disregar
d subtleties and go straight for the obvious!
“Of course the letter was meant to go astray! The police were to be set on the trail only when the murder was safely over. Your brother’s nightly walk provided you with the opportunity. And so successfully had the A B C terror taken hold on the public mind that the possibility of your guilt never occurred to anyone.
“After the death of your brother, of course, your object was accomplished. You had no wish to commit any more murders. On the other hand, if the murders stopped without reason, a suspicion of the truth might come to someone.
“Your stalking horse, Mr. Cust, had so successfully lived up to his role of the invisible—because insignificant—man, that so far no one had noticed that the same person had been seen in the vicinity of the three murders! To your annoyance, even his visit to Combeside had not been mentioned. The matter had passed completely out of Miss Grey’s head.
“Always daring, you decided that one more murder must take place but this time the trail must be well blazed.
“You selected Doncaster for the scene of operations.
“Your plan was very simple. You yourself would be on the scene in the nature of things. Mr. Cust would be ordered to Doncaster by his firm. Your plan was to follow him round and trust to opportunity. Everything fell out well. Mr. Cust went to a cinema. That was simplicity itself. You sat a few seats away from him. When he got up to go, you did the same. You pretended to stumble, leaned over and stabbed a dozing man in the row in front, slid the A B C on to his knees and managed to collide heavily with Mr. Cust in the darkened doorway, wiping the knife on his sleeve and slipping it into his pocket.
“You were not in the least at pains to choose a victim whose name began with D. Anyone would do! You assumed—and quite rightly—that it would be considered to be a mistake. There was sure to be someone whose name began with D not far off in the audience. It would be assumed that he had been intended to be the victim.
“And now, my friends, let us consider the matter from the point of view of the false A B C—from the point of view of Mr. Cust.
“The Andover crime means nothing to him. He is shocked and surprised by the Bexhill crime—why, he himself was there about the time! Then comes the Churston crime and the headlines in the newspapers. An A B C crime at Andover when he was there, an A B C crime at Bexhill, and now another close by…Three crimes and he has been at the scene of each of them. Persons suffering from epilepsy often have blanks when they cannot remember what they have done…Remember that Cust was a nervous, highly neurotic subject and extremely suggestible.
“Then he receives the order to go to Doncaster.
“Doncaster! And the next A B C crime is to be in Doncaster. He must have felt as though it was fate. He loses his nerve, fancies his landlady is looking at him suspiciously, and tells her he is going to Cheltenham.
“He goes to Doncaster because it is his duty. In the afternoon he goes to a cinema. Possibly he dozes off for a minute or two.
“Imagine his feelings when on his return to his inn he discovers that there is blood on his coat sleeve and a blood-stained knife in his pocket. All his vague forebodings leap into certainty.
“He—he himself—is the killer! He remembers his headaches—his lapses of memory. He is quite sure of the truth—he, Alexander Bonaparte Cust, is a homicidal lunatic.
“His conduct after that is the conduct of a hunted animal. He gets back to his lodgings in London. He is safe there—known. They think he has been in Cheltenham. He has the knife with him still—a thoroughly stupid thing to do, of course. He hides it behind the hall stand.
“Then, one day, he is warned that the police are coming. It is the end! They know!
“The hunted animal does his last run….
“I don’t know why he went to Andover—a morbid desire, I think, to go and look at the place where the crime was committed—the crime he committed though he can remember nothing about it….
“He has no money left—he is worn out…his feet lead him of his own accord to the police station.
“But even a cornered beast will fight. Mr. Cust fully believes that he did the murders but he sticks strongly to his plea of innocence. And he holds with desperation to that alibi for the second murder. At least that cannot be laid to his door.
“As I say, when I saw him, I knew at once that he was not the murderer and that my name meant nothing to him. I knew, too, that he thought himself the murderer!
“After he had confessed his guilt to me, I knew more strongly than ever that my own theory was right.”
“Your theory,” said Franklin Clarke, “is absurd!”
Poirot shook his head.
“No, Mr. Clarke. You were safe enough so long as no one suspected you. Once you were suspected proofs were easy to obtain.”
“Proofs?”
“Yes. I found the stick that you used in the Andover and Churston murders in a cupboard at Combeside. An ordinary stick with a thick knob handle. A section of wood had been removed and melted lead poured in. Your photograph was picked out from half a dozen others by two people who saw you leaving the cinema when you were supposed to be on the race course at Doncaster. You were identified at Bexhill the other day by Milly Higley and a girl from the Scarlet Runner Roadhouse, where you took Betty Barnard to dine on the fatal evening. And finally—most damning of all—you overlooked a most elementary precaution. You left a fingerprint on Cust’s typewriter—the typewriter that, if you are innocent, you could never have handled.”