‘For God’s sake, Thompson, don’t speak so glibly of the next crime,’ said Sir Lionel irritably. ‘We’re going to do all we can to prevent another crime.’

Dr Thompson held his peace and blew his nose with some violence.

‘Have it your own way,’ the noise seemed to say. ‘If you won’t face facts—’

The Assistant Commissioner turned to Poirot.

‘I see what you’re driving at, but I’m not quite clear yet.’

‘I ask myself,’ said Poirot, ‘what passes exactly in the mind of the murderer? He kills, it would seem from his letters, pour le sport—to amuse himself. Can that really be true? And even if it is true, on what principle does he select his victims apart from the merely alphabetical one? If he kills merely to amuse himself he would not advertise the fact, since, otherwise, he could kill with impunity. But no, he seeks, as we all agree, to make the splash in the public eye—to assert his personality. In what way has his personality been suppressed that one can connect with the two victims he has so far selected? A final suggestion: Is his motive direct personal hatred of me, of Hercule Poirot? Does he challenge me in public because I have (unknown to myself) vanquished him somewhere in the course of my career? Or is his animosity impersonal—directed against a foreigner? And if so, what again has led to that? What injury has he suffered at a foreigner’s hand?’

‘All very suggestive questions,’ said Dr Thompson.

Inspector Crome cleared his throat.

‘Oh, yes? A little unanswerable at present, perhaps.’

‘Nevertheless, my friend,’ said Poirot, looking straight at him, ‘it is there, in those questions, that the solution lies. If we knew the exact reason—fantastic, perhaps, to us—but logical to him—of why our madman commits these crimes, we should know, perhaps, who the next victim is likely to be.’

Crome shook his head.

‘He selects them haphazard—that’s my opinion.’

‘The magnanimous murderer,’ said Poirot.

‘What’s that you say?’

‘I said—the magnanimous murderer! Franz Ascher would have been arrested for the murder of his wife—Donald Fraser might have been arrested for the murder of Betty Barnard—if it had not been for the warning letters of A B C. Is he, then, so soft-hearted that he cannot bear others to suffer for something they did not do?’

‘I’ve known stranger things happen,’ said Dr Thompson. ‘I’ve known men who’ve killed half a dozen victims all broken up because one of their victims didn’t die instantaneously and suffered pain. All the same, I don’t think that that is our fellow’s reason. He wants the credit of these crimes for his own honour and glory. That’s the explanation that fits best.’

‘We’ve come to no decision about the publicity business,’ said the Assistant Commissioner.

‘If I may make a suggestion, sir,’ said Crome. ‘Why not wait till the receipt of the next letter? Make it public then—special editions, etc. It will make a bit of a panic in the particular town named, but it will put everyone whose name begins with C on their guard, and it’ll put A B C on his mettle. He’ll be determined to succeed. And that’s when we’ll get him.’