Ruth said sharply:

‘Are we to understand, M. Poirot, that you have definitely ascertained the cause of my father’s suicide?’

Poirot shook his head.

‘No, madame.’

‘Then what is all this rigmarole about?’

Poirot said quietly:

‘I do not know the cause of Sir Gervase Chevenix-Gore’s suicide, because Sir Gervase Chevenix-Gore did not commit suicide. He did not kill himself. He was killed…’

‘Killed?’ Several voices echoed the word. Startled faces were turned in Poirot’s direction. Lady Chevenix-Gore looked up, said, ‘Killed? Oh, no!’ and gently shook her head.

‘Killed, did you say?’ It was Hugo who spoke now. ‘Impossible. There was no one in the room when we broke in. The window was fastened. The door was locked on the inside, and the key was in my uncle’s pocket. How could he have been killed?’

‘Nevertheless, he was killed.’

‘And the murderer escaped through the keyhole, I suppose?’ said Colonel Bury sceptically. ‘Or flew up the chimney?’

‘The murderer,’ said Poirot, ‘went out through the window. I will show you how.’

He repeated his manoeuvres with the window.

‘You see?’ he said. ‘That was how it was done! From the first I could not consider it likely that Sir Gervase had committed suicide. He had pronounced egomania, and such a man does not kill himself.

‘And there were other things! Apparently, just before his death, Sir Gervase had sat down at his desk, scrawled the word SORRY on a sheet of note-paper and had then shot himself. But before this last action he had, for some reason or other altered the position of his chair, turning it so that it was sideways to the desk. Why? There must be some reason. I began to see light when I found, sticking to the base of a heavy bronze statuette, a tiny sliver of looking-glass…

‘I asked myself, how does a sliver of broken looking-glass come to be there?—and an answer suggested itself to me. The mirror had been broken, not by a bullet, but by being struck with the heavy bronze figure. That mirror had been broken deliberately.

‘But why? I returned to the desk and looked down at the chair. Yes, I saw now. It was all wrong. No suicide would turn his chair round, lean over the edge of it, and then shoot himself. The whole thing was arranged. The suicide was a fake!

‘And now I come to something very important. The evidence of Miss Cardwell. Miss Cardwell said that she hurried downstairs last night because she thought that the second gong had sounded. That is to say, she thought that she had already heard the first gong.

‘Now observe, if Sir Gervase was sitting at his desk in the normal fashion when he was shot, where would the bullet go? Travelling in a straight line, it would pass through the door, if the door were open, and finally hit the gong!

‘You see now the importance of Miss Cardwell’s statement? No one else heard the first gong, but, then, her room is situated immediately above this one, and she was in the best position for hearing it. It would consist of only one single note, remember.