As far as I can see, of the people in the house, only two could have had the chance of doing it. Ralph Paton and Flora Ackroyd.' 'My dear Caroline-' 'Now, James, don't interrupt me. I know what I'm talking about. Parker met her outside the door, didn't he?

He didn't hear her uncle saying goodnight to her. She could have killed him then and there.' 'Caroline!' 'I'm not saying she did, James. I'm saying she could have done. As a matter of fact, though. Flora is like all these young girls nowadays, with no veneration for their betters and thinking they know best on every subject under the sun, I don't for a minute believe she'd kill even a chicken.

But there it is. Mr Raymond and Major Blunt have alibis.

Mrs Ackroyd's got an alibi. Even that Russell woman seems to have one - and a good job for her it is she has. Who is left? Only Ralph and Flora! And say what you will, I don't believe Ralph Paton is a murderer. A boy we've known all our lives.' Poirot was silent for a minute, watching the curling smoke rise from his cigarette. When at last he spoke, it was in a gentle far-away voice that produced a curious impression.

It was totally unlike his usual manner.

'Let us take a man - a very ordinary man. A man with no idea of murder in his heart. There is in him somewhere a strain of weakness - deep down. It has so far never been called into play. Perhaps it never will be - and if so he will go to his grave honoured and respected by everyone. But let us suppose that something occurs. He is in difficulties - or perhaps not that even. He may stumble by accident on a secret - a secret involving life or death to someone. And his first impulse will be to speak out - to do his duty as an honest citizen. And then the strain of weakness tells. Here is a chance of money - a great amount of money. He wants money - he desires it - and it is so easy. He has to do nothing for it - just keep silence. That is the beginning. The desire for money grows. He must have more - and more! He is intoxicated by the gold mine which has opened at his feet.

He becomes greedy. And in his greed he overreaches himself. One can press a man as far as one likes - but with a woman one must not press too far. For a woman has at heart a great desire to speak the truth. How many husbands who have deceived their wives go comfortably to their graves, carrying their secret with them! How many wives who have deceived their husbands wreck their lives by throwing the fact in those same husbands' teeth! They have been pressed too far. In a reckless moment (which they will afterwards regret, bien entendu) they fling safety to the winds and turn at bay, proclaiming the truth with great momentary satisfaction to themselves. So it was, I think, in this case. The strain was too great. And so there came your proverb, the death of the goose that laid the golden eggs. But that is not the end. Exposure faced the man of whom we are speaking.

And he is not the same man he was - say, a year ago. His moral fibre is blunted. He is desperate. He is fighting a losing battle, and he is prepared to take any means that come to his hand, for exposure means ruin to him. And so - the dagger strikes!' He was silent for a moment. It was as though he had laid a spell upon the room. I cannot try to describe the impression his words produced. There was something in the merciless analysis, and the ruthless power of vision which struck fear into both of us.

'Afterwards,' he went on softly, 'the dagger removed, he will be himself again, normal, kindly. But if the need again arises, then once more he will strike.' Caroline roused herself at last.

'You are speaking of Ralph Paton,' she said. 'You may be right, you may not, but you have no business to condemn a man unheard.' The telephone bell rang sharply. I went out into the hall, and took off the receiver.

'What?' I said. 'Yes. Dr Sheppard speaking.' I listened for a minute or two, then replied briefly. Replacing the receiver, I went back into the drawing-room.

'Poirot,' I said, 'they have detained a man at Liverpool.

His name is Charles Kent, and he is believed to be the stranger who visited Femly that night. They want me to go to Liverpool at once and identify him.'

Half an hour later saw Poirot, myself, and Inspector Raglan in the train on the way to Liverpool. The inspector was clearly very excited.

'We may get a line on the blackmailing part of the business, if on nothing else,' he declared jubilantly. 'He's a rough customer, this fellow, by what I heard over the phone. Takes dope, too. We ought to find it easy to get what we want out of him. If there was the shadow of a motive, nothing's more likely than that he killed Mr Ackroyd. But in that case, why is young Paton keeping out of the way. The whole thing's a muddle - that's what it is. By the way, M. Poirot, you were quite right about those fingerprints. They were Mr Ackroyd's own. I had rather the same idea myself, but I dismissed it as hardly feasible.' I smiled to myself. Inspector Raglan was so very plainly saving his face.

'As regard this man,' said Poirot, 'he is not yet arrested, eh?' 'No, detained under suspicion.' 'And what account does he give of himself?' 'Precious little,' said the inspector, with a grin. 'He's a wary bird, I gather. A lot of abuse, but very little more.' On arrival at Liverpool I was surpised to find that Poirot was welcomed with acclamation. Superintendent Hayes, who met us, had worked with Poirot over some case long ago, and had evidently an exaggerated opinion of his powers.

'Now we've got M. Poirot here we shan't be long,' he said cheerfully. 'I thought you'd retired, moosior?' 'So I had, my good Hayes, so I had. But how tedious is retirement! You cannot imagine to yourself the monotony with which day comes after day.' 'Very likely. So you've come to have a look at our own particular find? Is this Dr Sheppard? Think you'll be able to identify him, sir?' 'I'm not very sure,' I said doubtfully.

'How did you get hold of him?' inquired Poirot.

'Description was circulated, as you know. In the press and privately. Not much to go on, I admit. This fellow has an American accent all right, and he doesn't deny that he was near King's Abbot that night. Just asks what the hell it is to do with us, and that he'll see us in - before he answers any questions.' 'Is it permitted that I, too, see him?' asked Poirot.

The superintendent closed one eye knowingly.

'Very glad to have you, sir. You've got permission to do anything you please. Inspector Japp of Scotland Yard was asking after you the other day. Said he'd heard you were connected unofficially with this case. Where's Captain Paton hiding, sir, can you tell me that?' 'I doubt if it would be wise at the present juncture,' said Poirot primly, and I bit my lips to prevent a smile.

The little man really did it very well.

After some further parley, we were taken to interview the prisoner.

He was a young fellow, I should say not more than twenty-two or three. Tall, thin, with slightly shaking hands, and the evidences of considerable physical strength somewhat run to seed. His hair was dark, but his eyes were blue and shifty, seldom meeting a glance squarely. I had all along cherished the illusion that there was something familiar about the figure I had met that night, but if this were indeed he, I was completely mistaken. He did not remind me in the least of anyone I knew.

'Now then, Kent,' said the superintendent. 'Stand up.

Here are some visitors come to see you. Recognize any of them?' Kent glared at us sullenly, but did not reply. I saw his glance waver over the three of us, and come back to rest on me.

'Well, sir,' said the superintendent to me, 'what do you say?' 'The height's the same,' I said, 'and as far as general appearance goes it might well be the man in question.