Behind the whimsicality there was something earnest in his appeal. He had come to think very highly of the mental powers of this frail old-fashioned maiden lady. He looked across at her with something very like hope in his eyes.

Miss Marple coughed and smoothed her lace.

‘It does remind me a little of Annie Poultny,’ she admitted. ‘Of course the letter is perfectly plain—both to Mrs Bantry and myself. I don’t mean the Church Social letter, but the other one. You living so much in London and not being a gardener, Sir Henry, would not have been likely to notice.’

‘Eh?’ said Sir Henry. ‘Notice what?’

Mrs Bantry reached out a hand and selected a catalogue. She opened it and read aloud with gusto:

‘Dr Helmuth Spath. Pure lilac, a wonderfully fine flower, carried on exceptionally long and stiff stem. Splendid for cutting and garden decoration. A novelty of striking beauty.

‘Edgar Jackson. Beautifully shaped chrysanthemum-like flower of a distinct brick-red colour.

‘Amos Perry. Brilliant red, highly decorative.

‘Tsingtau. Brilliant orange-red, showy garden plant and lasting cut flower.

‘Honesty—’

‘With a capital H, you remember,’ murmured Miss Marple.

‘Honesty. Rose and white shades, enormous perfect shaped flower.’

Mrs Bantry flung down the catalogue, and said with immense explosive force:

‘Dahlias!’

‘And their initial letters spell “DEATH”, explained Miss Marple.

‘But the letter came to Dr Rosen himself,’ objected Sir Henry.

‘That was the clever part of it,’ said Miss Marple. ‘That and the warning in it. What would he do, getting a letter from someone he didn’t know, full of names he didn’t know. Why, of course, toss it over to his secretary.’

‘Then, after all—’

‘Oh, no!’ said Miss Marple. ‘Not the secretary. Why, that’s what makes it so perfectly clear that it wasn’t him. He’d never have let that letter be found if so. And equally he’d never have destroyed a letter to himself with a German stamp on it. Really, his innocence is—if you’ll allow me to use the word—just shining.’

‘Then who—’

‘Well, it seems almost certain—as certain as anything can be in this world. There was another person at the breakfast table, and she would—quite naturally under the circumstances—put out her hand for the letter and read it. And that would be that. You remember that she got a gardening catalogue by the same post—’

‘Greta Rosen,’ said Sir Henry, slowly. ‘Then her visit to me—’

‘Gentlemen never see through these things,’ said Miss Marple. ‘And I’m afraid they often think we old women are—well, cats, to see things the way we do. But there it is. One does know a great deal about one’s own sex, unfortunately. I’ve no doubt there was a barrier between them. The young man felt a sudden inexplicable repulsion. He suspected, purely through instinct, and couldn’t hide the suspicion. And I really think that the girl’s visit to you was just pure spite. She was safe enough really; but she just went out of her way to fix your suspicions definitely on poor Mr Templeton. You weren’t nearly so sure about him until after her visit.’