The following morning saw us at a conference of powers. The Chief Constable of Sussex, the Assistant Commissioner of the CID, Inspector Glen from Andover, Superintendent Carter of the Sussex police, Japp and a younger inspector called Crome, and Dr Thompson, the famous alienist, were all assembled together. The postmark on this letter was Hampstead, but in Poirot’s opinion little importance could be attached to this fact.

The matter was discussed fully. Dr Thompson was a pleasant middle-aged man who, in spite of his learning, contented himself with homely language, avoiding the technicalities of his profession.

‘There’s no doubt,’ said the Assistant Commissioner, ‘that the two letters are in the same hand. Both were written by the same person.’

‘And we can fairly assume that that person was responsible for the Andover murder.’

‘Quite. We’ve now got definite warning of a second crime scheduled to take place on the 25th—the day after tomorrow—at Bexhill. What steps can be taken?’

The Sussex Chief Constable looked at his superintendent.

‘Well, Carter, what about it?’

The superintendent shook his head gravely.

‘It’s difficult, sir. There’s not the least clue towards whom the victim may be. Speaking fair and square, what steps can we take?’

‘A suggestion,’ murmured Poirot.

Their faces turned to him.

‘I think it possible that the surname of the intended victim will begin with the letter B.’

‘That would be something,’ said the superintendent doubtfully.

‘An alphabetical complex,’ said Dr Thompson thoughtfully.

‘I suggest it as a possibility—no more. It came into my mind when I saw the name Ascher clearly written over the shop door of the unfortunate woman who was murdered last month. When I got the letter naming Bexhill it occurred to me as a possibility that the victim as well as the place might be selected by an alphabetical system.’

‘It’s possible,’ said the doctor. ‘On the other hand, it may be that the name Ascher was a coincidence—that the victim this time, no matter what her name is, will again be an old woman who keeps a shop. We’re dealing, remember, with a madman. So far he hasn’t given us any clue as to motive.’

‘Has a madman any motive, sir?’ asked the superintendent sceptically.

‘Of course he has, man. A deadly logic is one of the special characteristics of acute mania. A man may believe himself divinely appointed to kill clergymen—or doctors—or old women in tobacco shops—and there’s always some perfectly coherent reason behind it. We mustn’t let the alphabetical business run away with us. Bexhill succeeding to Andover may be a mere coincidence.’

‘We can at least take certain precautions, Carter, and make a special note of the B’s, especially small shopkeepers, and keep a watch on all small tobacconists and newsagents looked after by a single person. I don’t think there’s anything more we can do than that. Naturally, keep tabs on all strangers as far as possible.’

The superintendent uttered a groan.

‘With the schools breaking up and the holidays beginning? People are fairly flooding into the place this week.’