‘You were not in the least at pains to choose a victim whose name began with D. Anyone would do! You assumed—and quite rightly—that it would be considered to be a mistake. There was sure to be someone whose name began with D not far off in the audience. It would be assumed that he had been intended to be the victim.

‘And now, my friends, let us consider the matter from the point of view of the false A B C—from the point of view of Mr Cust.

‘The Andover crime means nothing to him. He is shocked and surprised by the Bexhill crime—why, he himself was there about the time! Then comes the Churston crime and the headlines in the newspapers. An A B C crime at Andover when he was there, an A B C crime at Bexhill, and now another close by…Three crimes and he has been at the scene of each of them. Persons suffering from epilepsy often have blanks when they cannot remember what they have done…Remember that Cust was a nervous, highly neurotic subject and extremely suggestible.

‘Then he receives the order to go to Doncaster.

‘Doncaster! And the next A B C crime is to be in Doncaster. He must have felt as though it was fate. He loses his nerve, fancies his landlady is looking at him suspiciously, and tells her he is going to Cheltenham.

‘He goes to Doncaster because it is his duty. In the afternoon he goes to a cinema. Possibly he dozes off for a minute or two.

‘Imagine his feelings when on his return to his inn he discovers that there is blood on his coat sleeve and a blood-stained knife in his pocket. All his vague forebodings leap into certainty.

‘He—he himself—is the killer! He remembers his headaches—his lapses of memory. He is quite sure of the truth—he, Alexander Bonaparte Cust, is a homicidal lunatic.

‘His conduct after that is the conduct of a hunted animal. He gets back to his lodgings in London. He is safe there—known. They think he has been in Cheltenham. He has the knife with him still—a thoroughly stupid thing to do, of course. He hides it behind the hall stand.

‘Then, one day, he is warned that the police are coming. It is the end! They know!

‘The hunted animal does his last run…

‘I don’t know why he went to Andover—a morbid desire, I think, to go and look at the place where the crime was committed—the crime he committed though he can remember nothing about it…

‘He has no money left—he is worn out…his feet lead him of his own accord to the police station.

‘But even a cornered beast will fight. Mr Cust fully believes that he did the murders but he sticks strongly to his plea of innocence. And he holds with desperation to that alibi for the second murder. At least that cannot be laid to his door.

‘As I say, when I saw him, I knew at once that he was not the murderer and that my name meant nothing to him. I knew, too, that he thought himself the murderer!