She looked at Poirot.

‘You don’t know what I did then?’

‘Oh yes, I do. I found the bag in the wastepaper basket. It was very clever, that idea of yours. You did what children love to do. You blew up the bag and then hit it. It made a satisfactory big bang. You threw the bag into the wastepaper basket and rushed out into the hall. You had established the time of the suicide—and an alibi for yourself. But there was still one thing that worried you. You had not had time to pick up the bullet. It must be somewhere near the gong. It was essential that the bullet should be found in the study somewhere near the mirror. I didn’t know when you had the idea of taking Colonel Bury’s pencil—’

‘It was just then,’ said Miss Lingard. ‘When we all came in from the hall. I was surprised to see Ruth in the room. I realized she must have come from the garden through the window. Then I noticed Colonel Bury’s pencil lying on the bridge table. I slipped it into my bag. If, later, anyone saw me pick up the bullet, I could pretend it was the pencil. As a matter of fact, I didn’t think anyone saw me pick up the bullet. I dropped it by the mirror while you were looking at the body. When you tackled me on the subject, I was very glad I had thought of the pencil.’

‘Yes, that was clever. It confused me completely.’

‘I was afraid someone must hear the real shot, but I knew everyone was dressing for dinner, and would be shut away in their rooms. The servants were in their quarters. Miss Cardwell was the only one at all likely to hear it, and she would probably think it was a backfire. What she did hear was the gong. I thought—I thought everything had gone without a hitch…’

Mr Forbes said slowly in his precise tones:

‘This is a most extraordinary story. There seems no motive—’

Miss Lingard said clearly: ‘There was a motive…’

She added fiercely:

‘Go on, ring up the police! What are you waiting for?’

Poirot said gently:

‘Will you all please leave the room? Mr Forbes, ring up Major Riddle. I will stay here till he comes.’

Slowly, one by one, the family filed out of the room. Puzzled, uncomprehending, shocked, they cast abashed glances at the trim, upright figure with its neatly-parted grey hair.

Ruth was the last to go. She stood, hesitating in the doorway.

‘I don’t understand.’ She spoke angrily, defiantly, accusing Poirot. ‘Just now, you thought I had done it.’

‘No, no,’ Poirot shook his head. ‘No, I never thought that.’

Ruth went out slowly.

Poirot was left with the little middle-aged prim woman who had just confessed to a cleverly-planned and cold-blooded murder.

‘No,’ said Miss Lingard. ‘You didn’t think she had done it. You accused her to make me speak. That’s right, isn’t it?’