Radnor accepted the invitation. I ordered two whiskies and sodas and a cup of chocolate. The last order caused consternation, and I much doubted whether it would ever put in an appearance.
‘Of course,’ continued Poirot, ‘I have a good deal of experience in matters of this kind. And I see only one loophole of escape for our friend.’
‘What is it?’
‘That you should sign this paper.’
With the suddenness of a conjuror, he produced a sheet of paper covered with writing.
‘What is it?’
‘A confession that you murdered Mrs Pengelley.’
There was a moment’s pause; then Radnor laughed.
‘You must be mad!’
‘No, no, my friend, I am not mad. You came here; you started a little business; you were short of money. Mr Pengelley was a man very well-to-do. You met his niece; she was inclined to smile upon you. But the small allowance that Pengelley might have given her upon her marriage was not enough for you. You must get rid of both the uncle and the aunt; then the money would come to her, since she was the only relative. How cleverly you set about it! You made love to that plain middle-aged woman until she was your slave. You implanted in her doubts of her husband. She discovered first that he was deceiving her—then, under your guidance, that he was trying to poison her. You were often at the house; you had opportunities to introduce the arsenic into her food. But you were careful never to do so when her husband was away. Being a woman, she did not keep her suspicions to herself. She talked to her niece; doubtless she talked to other women friends. Your only difficulty was keeping up separate relations with the two women, and even that was not so difficult as it looked. You explained to the aunt that, to allay the suspicions of her husband, you had to pretend to pay court to the niece. And the younger lady needed little convincing—she would never seriously consider her aunt as a rival.
‘But then Mrs Pengelley made up her mind, without saying anything to you, to consult me. If she could be really assured, beyond any possible doubt, that her husband was trying to poison her, she would feel justified in leaving him, and linking her life with yours—which is what she imagined you wanted her to do. But that did not suit your book at all. You did not want a detective prying around. A favourable minute occurs. You are in the house when Mr Pengelley is getting some gruel for his wife, and you introduce the fatal dose. The rest is easy. Apparently anxious to hush matters up, you secretly foment them. But you reckoned without Hercule Poirot, my intelligent young friend.’
Radnor was deadly pale, but he still endeavoured to carry off matters with a high hand.
‘Very interesting and ingenious, but why tell me all this?’
‘Because, monsieur, I represent—not the law, but Mrs Pengelley. For her sake, I give you a chance of escape. Sign this paper, and you shall have twenty-four hours’ start—twenty-four hours before I place it in the hands of the police.’
Radnor hesitated.
‘You can’t prove anything.’
‘Can’t I? I am Hercule Poirot. Look out of the window, monsieur. There are two men in the street. They have orders not to lose sight of you.’
Radnor strode across to the window and pulled aside the blind, then shrank back with an oath.
‘You see, monsieur? Sign—it is your best chance.’
‘What guarantee have I—’
‘That I shall keep faith? The word of Hercule Poirot. You will sign? Good. Hastings, be so kind as to pull that left-hand blind half-way up. That is the signal that Mr Radnor may leave unmolested.’
White, muttering oaths, Radnor hurried from the room. Poirot nodded gently.
‘A coward! I always knew it.’
‘It seems to me, Poirot, that you’ve acted in a criminal manner,’ I cried angrily. ‘You always preach against sentiment. And here you are letting a dangerous criminal escape out of sheer sentimentality.’
‘That was not sentiment—that was business,’ replied Poirot. ‘Do you not see, my friend, that we have no shadow of proof against him? Shall I get up and say to twelve stolid Cornishmen that I, Hercule Poirot, know? They would laugh at me. The only chance was to frighten him and get a confession that way. Those two loafers that I noticed outside came in very useful. Pull down the blind again, will you, Hastings. Not that there was any reason for raising it. It was part of our mise en scène.