“Wait a minute. I don’t see why he wished to be arrested?”
“Because, mon ami, it is the law of your country that a man once acquitted can never be tried again for the same offence. Aha! but it was clever–his idea! Assuredly, he is a man of method. See here, he knew that in his position he was bound to be suspected, so he conceived the exceedingly clever idea of preparing a lot of manufactured evidence against himself. He wished to be arrested. He would then produce his irreproachable alibi–and, hey presto, he was safe for life!”
“But I still don’t see how he managed to prove his alibi, and yet go to the chemist’s shop?”
Poirot stared at me in surprise.
“Is it possible? My poor friend! You have not yet realized that it was Miss Howard who went to the chemist’s shop?”
“Miss Howard?”
“But, certainly. Who else? It was most easy for her. She is of a good height, her voice is deep and manly; moreover, remember, she and Inglethorp are cousins, and there is a distinct resemblance between them, especially in their gait and bearing. It was simplicity itself. They are a clever pair!”
“I am still a little fogged as to how exactly the bromide business was done,” I remarked.
“Bon! I will reconstruct for you as far as possible. I am inclined to think that Miss Howard was the master mind in that affair. You remember her once mentioning that her father was a doctor? Possibly she dispensed his medicines for him, or she may have taken the idea from one of the many books lying about when Mademoiselle Cynthia was studying for her exam. Anyway, she was familiar with the fact that the addition of a bromide to a mixture containing strychnine would cause the precipitation of the latter. Probably the idea came to her quite suddenly. Mrs. Inglethorp had a box of bromide powders, which she occasionally took at night. What could be easier than quietly to dissolve one or more of those powders in Mrs. Inglethorp’s large sized bottle of medicine when it came from Coot’s? The risk is practically nil. The tragedy will not take place until nearly a fortnight later. If anyone has seen either of them touching the medicine, they will have forgotten it by that time. Miss Howard will have engineered her quarrel, and departed from the house. The lapse of time, and her absence, will defeat all suspicion. Yes, it was a clever idea! If they had left it alone, it is possible the crime might never have been brought home to them. But they were not satisfied. They tried to be too clever–and that was their undoing.”
Poirot puffed at his tiny cigarette, his eyes fixed on the ceiling.
“They arranged a plan to throw suspicion on John Cavendish, by buying strychnine at the village chemist’s, and signing the register in his hand-writing.
“On Monday Mrs. Inglethorp will take the last dose of her medicine. On Monday, therefore, at six o’clock, Alfred Inglethorp arranges to be seen by a number of people at a spot far removed from the village. Miss Howard has previously made up a cock and bull story about him and Mrs. Raikes to account for his holding his tongue afterwards. At six o’clock, Miss Howard, disguised as Alfred Inglethorp, enters the chemist’s shop, with her story about a dog, obtains the strychnine, and writes the name of Alfred Inglethorp in John’s handwriting, which she had previously studied carefully.
“But, as it will never do if John, too, can prove an alibi, she writes him an anonymous note–still copying his hand-writing –which takes him to a remote spot where it is exceedingly unlikely that anyone will see him.
“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.