“So far, all goes well. Miss Howard goes back to Middlingham. Alfred Inglethorp returns to Styles. There is nothing that can compromise him in any way, since it is Miss Howard who has the strychnine, which, after all, is only wanted as a blind to throw suspicion on John Cavendish.
“But now a hitch occurs. Mrs. Inglethorp does not take her medicine that night. The broken bell, Cynthia’s absence— arranged by Inglethorp through his wife—all these are wasted. And then—he makes his slip.
“Mrs. Inglethorp is out, and he sits down to write to his accomplice, who, he fears, may be in a panic at the nonsuccess of their plan. It is probable that Mrs. Inglethorp returned earlier than he expected. Caught in the act, and somewhat flurried he hastily shuts and locks his desk. He fears that if he remains in the room he may have to open it again, and that Mrs. Inglethorp might catch sight of the letter before he could snatch it up. So he goes out and walks in the woods, little dreaming that Mrs. Inglethorp will open his desk, and discover the incriminating document.
“But this, as we know, is what happened. Mrs. Inglethorp reads it, and becomes aware of the perfidy of her husband and Evelyn Howard, though, unfortunately, the sentence about the bromides conveys no warning to her mind. She knows that she is in danger—but is ignorant of where the danger lies. She decides to say nothing to her husband, but sits down and writes to her solicitor, asking him to come on the morrow, and she also determines to destroy immediately the will which she has just made. She keeps the fatal letter.”
“It was to discover that letter, then, that her husband forced the lock of the despatch-case?”
“Yes, and from the enormous risk he ran we can see how fully he realized its importance. That letter excepted, there was absolutely nothing to connect him with the crime.”
“There’s only one thing I can’t make out, why didn’t he destroy it at once when he got hold of it?”
“Because he did not dare take the biggest risk of all—that of keeping it on his own person.”
“I don’t understand.”
“Look at it from his point of view. I have discovered that there were only five short minutes in which he could have taken it—the five minutes immediately before our own arrival on the scene, for before that time Annie was brushing the stairs, and would have seen anyone who passed going to the right wing. Figure to yourself the scene! He enters the room, unlocking the door by means of one of the other doorkeys—they were all much alike. He hurries to the despatch-case—it is locked, and the keys are nowhere to be seen. That is a terrible blow to him, for it means that his presence in the room cannot be concealed as he had hoped. But he sees clearly that everything must be risked for the sake of that damning piece of evidence. Quickly, he forces the lock with a penknife, and turns over the papers until he finds what he is looking for.
“But now a fresh dilemma arises: he dare not keep that piece of paper on him. He may be seen leaving the room—he may be searched. If the paper is found on him, it is certain doom. Probably, at this minute, too, he hears the sounds below of Mr. Wells and John leaving the boudoir. He must act quickly. Where can he hide this terrible slip of paper? The contents of the waste-paper-basket are kept and in any case, are sure to be examined. There are no means of destroying it; and he dare not keep it. He looks round, and he sees—what do you think, mon ami?”
I shook my head.
“In a moment, he has torn the letter into long thin strips, and rolling them up into spills he thrusts them hurriedly in amongst the other spills in the vase on the mantle-piece.”
I uttered an exclamation.
“No one would think of looking there,” Poirot continued. “And he will be able, at his leisure, to come back and destroy this solitary piece of evidence against him.”
“Then, all the time, it was in the spill vase in Mrs. Inglethorp’s bedroom, under our very noses?” I cried.
Poirot nodded.
“Yes, my friend. That is where I discovered my ‘last link,’ and I owe that very fortunate discovery to you.”
“To me?”
“Yes. Do you remember telling me that my hand shook as I was straightening the ornaments on the mantel-piece?”
“Yes, but I don’t see——”
“No, but I saw. Do you know, my friend, I remembered that earlier in the morning, when we had been there together, I had straightened all the objects on the mantel-piece. And, if they were already straightened, there would be no need to straighten them again, unless, in the meantime, some one else had touched them.”
“Dear me,” I murmured, “so that is the explanation of your extraordinary behaviour. You rushed down to Styles, and found it still there?”
“Yes, and it was a race for time.”
“But I still can’t understand why Inglethorp was such a fool as to leave it there when he had plenty of opportunity to destroy it.”
“Ah, but he had no opportunity. I saw to that.”
“You?”
“Yes. Do you remember reproving me for taking the household into my confidence on the subject?”
“Yes.”
“Well, my friend, I saw there was just one chance. I was not sure then if Inglethorp was the criminal or not, but if he was I reasoned that he would not have the paper on him, but would have hidden it somewhere, and by enlisting the sympathy of the household I could effectually prevent his destroying it. He was already under suspicion, and by making the matter public I secured the services of about ten amateur detectives, who would be watching him unceasingly, and being himself aware of their watchfulness he would not dare seek further to destroy the document. He was therefore forced to depart from the house, leaving it in the spill vase.”
“But surely Miss Howard had ample opportunities of aiding him.”
“Yes, but Miss Howard did not know of the paper’s existence. In accordance with their prearranged plan, she never spoke to Alfred Inglethorp. They were supposed to be deadly enemies, and until John Cavendish was safely convicted they neither of them dared risk a meeting. Of course I had a watch kept on Mr. Inglethorp, hoping that sooner or later he would lead me to the hiding-place. But he was too clever to take any chances. The paper was safe where it was; since no one had thought of looking there in the first week, it was not likely they would do so afterwards. But for your lucky remark, we might never have been able to bring him to justice.”
“I understand that now; but when did you first begin to suspect Miss Howard?”
“When I discovered that she had told a lie at the inquest about the letter she had received from Mrs. Inglethorp.”
“Why, what was there to lie about?”
“You saw that letter? Do you recall its general appearance?”
“Yes—more or less.”
“You will recollect, then, that Mrs. Inglethorp wrote a very distinctive hand, and left large clear spaces between her words. But if you look at the date at the top of the letter you will notice that ‘July 17th’ is quite different in this respect. Do you see what I mean?”
“No,” I confessed, “I don’t.”
“You do not see that that letter was not written on the 17th, but on the 7th—the day after Miss Howard’s departure? The ‘1’ was written in before the ‘7’ to turn it into the ‘17th’.”
“But why?”
“That is exactly what I asked myself. Why does Miss Howard suppress the letter written on the 17th, and produce this faked one instead? Because she did not wish to show the letter of the 17th. Why, again? And at once a suspicion dawned in my mind. You