Agatha Christie: The Mysterious Affair at Styles

CHAPTER 13. POIROT EXPLAINS (continued)

"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 will remember my saying that it was wise to beware of people who were not telling you the truth."

"And yet," I cried indignantly, "after that, you gave me two reasons why Miss Howard could not have committed the crime!"

"And very good reasons too," replied Poirot. "For a long time they were a stumbling-block to me until I remembered a very significant fact: that she and Alfred Inglethorp were cousins. She could not have committed the crime single-handed, but the reasons against that did not debar her from being an accomplice. And, then, there was that rather over-vehement hatred of hers! It concealed a very opposite emotion. There was, undoubtedly, a tie of passion between them long before he came to Styles. They had already arranged their infamous plot--that he should marry this rich, but rather foolish old lady, induce her to make a will leaving her money to him, and then gain their ends by a very cleverly conceived crime. If all had gone as they planned, they would probably have left England, and lived together on their poor victim's money.

"They are a very astute and unscrupulous pair. While suspicion was to be directed against him, she would be making quiet preparations for a very different denouement. She arrives from Middlingham with all the compromising items in her possession. No suspicion attaches to her. No notice is paid to her coming and going in the house. She hides the strychnine and glasses in John's room. She puts the beard in the attic. She will see to it that sooner or later they are duly discovered."