‘Oh!’ said Jane. ‘Then it isn’t very interesting after all.’

‘Oh! but it is,’ said Miss Marple. ‘It’s just the one really interesting thing—the thing that made all the murderer’s plans go wrong.’

Everyone stared at the old lady.

‘I didn’t see it myself for two days,’ said Miss Marple. ‘I puzzled and puzzled—and then suddenly there it was, all clear. I went to the Inspector and asked him to try something and he did.’

‘What did you ask him to try?’

‘I asked him to fit that hat on the poor girl’s head—and of course he couldn’t. It wouldn’t go on. It wasn’t her hat, you see.’

Mrs Bantry stared.

‘But it was on her head to begin with?’

‘Not on her head—’

Miss Marple stopped a moment to let her words sink in, and then went on.

‘We took it for granted that it was poor Gladys’s body there; but we never looked at the face. She was face downwards, remember, and the hat hid everything.’

‘But she was killed?’

‘Yes, later. At the moment that we were telephoning to the police, Gladys Sanders was alive and well.’

‘You mean it was someone pretending to be her? But surely when you touched her—’

‘It was a dead body, right enough,’ said Miss Marple gravely.

‘But, dash it all,’ said Colonel Bantry, ‘you can’t get hold of dead bodies right and left. What did they do with the—the first corpse afterwards?’

‘He put it back,’ said Miss Marple. ‘It was a wicked idea—but a very clever one. It was our talk in the drawing-room that put it into his head. The body of poor Mary, the housemaid—why not use it? Remember, the Sanders’ room was up amongst the servants’ quarters. Mary’s room was two doors off. The undertakers wouldn’t come till after dark—he counted on that. He carried the body along the balcony (it was dark at five), dressed it in one of his wife’s dresses and her big red coat. And then he found the hat cupboard locked! There was only one thing to be done, he fetched one of the poor girl’s own hats. No one would notice. He put the sandbag down beside her. Then he went off to establish his alibi.

‘He telephoned to his wife—calling himself Mr Littleworth. I don’t know what he said to her—she was a credulous girl, as I said just now. But he got her to leave the bridge party early and not to go back to the Hydro, and arranged with her to meet him in the grounds of the Hydro near the fire escape at seven o’clock. He probably told her he had some surprise for her.

‘He returns to the Hydro with his friends and arranges that Miss Trollope and I shall discover the crime with him. He even pretends to turn the body over—and I stop him! Then the police are sent for, and he staggers out into the grounds.

‘Nobody asked him for an alibi after the crime. He meets his wife, takes her up the fire escape, they enter their room. Perhaps he has already told her some story about the body. She stoops over it, and he picks up his sandbag and strikes…Oh, dear! It makes me sick to think of, even now! Then quickly he strips off her coat and skirt, hangs them up, and dresses her in the clothes from the other body.