“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.”