‘You do not see what that means?’ he cried. ‘You do not see. Look! Look!’ He sprang forward to the chair where the victim had sat. ‘Did you notice how the body was? Not sitting square to the desk–no, sitting sideways to the desk, facing the window. Is that a natural way to commit suicide? Jamais, jamais! You write your apologia “sorry” on a piece of paper–you open the drawer, you take out the pistol, you hold it to your head and you fire. That is the way of suicide. But now consider murder! The victim sits at his desk, the murderer stands beside him–talking. And talking still–fires. Where does the bullet go then?’ He paused. ‘Straight through the head, through the door if it is open, and so–hits the gong.

‘Ah! you begin to see? That was the first gong–heard only by mademoiselle, since her room is above.

‘What does our murderer do next? Shuts the door, locks it, puts the key in the dead man’s pocket, then turns the body sideways in the chair, presses the dead man’s fingers on the pistol and then drops it by his side, cracks the mirror on the wall as a final spectacular touch –in short, “arranges” his suicide. Then out through the window, the bolt is shaken home, the murderer steps not on the grass, where footprints must show, but on the flower bed, where they can be smoothed out behind him, leaving no trace. Then back into the house, and at twelve minutes past eight, when he is alone in the drawing room, he fires a service revolver out of the drawing room window and dashes out into the hall. Is that how you did it, Mr Geoffrey Keene?’

Fascinated, the secretary stared at the accusing figure drawing nearer to him. Then, with a gurgling cry, he fell to the ground.

‘I think I am answered,’ said Poirot. ‘Captain Marshall, will you ring up the police?’ He bent over the prostrate form. ‘I fancy he will be still unconscious when they come.’

‘Geoffrey Keene,’ murmured Diana. ‘But what motive had he?’

‘I fancy that as secretary he had certain opportunities–accounts–cheques. Something awakened Mr Lytcham Roche’s suspicions. He sent for me.’

‘Why for you? Why not for the police?’