But Miss Marple did not at once go through the door and up the stairs. It was just two-thirty, and, a minute late, the Much Benham bus drew up outside the post-office door. It was one of the events of the day in St. Mary Mead. The post-mistress hurried out with parcels, parcels connected with the shop side of her business, for the post office also dealt in sweets, cheap books, and children's toys.

For some four minutes Miss Marple was alone in the post office.

Not till the postmistress returned to her post did Miss Marple go upstairs and explain to Miss Politt that she wanted her own grey crepe altered and made more fashionable if that were possible. Miss Politt promised to see what she could do.

The chief constable was rather astonished when Miss Marple's name was brought to him. She came in with many apologies. 'So sorry - so very sorry to disturb you. You are so busy, I know, but then you have always been so very kind, Colonel Melchett, and I felt I would rather come to you instead of to Inspector Slack. For one thing, you know, I should hate Constable Palk to get into any trouble. Strictly speaking, I suppose he shouldn't have touched anything at all.'

Colonel Melchett was slightly bewildered. He said, 'Palk? That's the St Mary Mead constable, isn't it? What has he been doing?'

'He picked up a pin, you know. It was in his tunic. And it occurred to me at the time that it was quite probably he had actually picked it up in Mrs. Spenlow's house.'

'Quite, quite. But, after all, you know, what's a pin? Matter of fact, he did pick the pin up just by Mrs. Spenlow's body. Came and told Slack about it yesterday - you put him up to that, I gather? Oughtn't to have touched anything, of course, but, as I said, what's a pin? It was only a common pin. Sort of thing any woman might use.'

'Oh no, Colonel Melchett, that's where you're wrong. To a man's eye, perhaps, it looked like an ordinary pin, but it wasn't. It was a special pin, a very thin pin, the kind you buy by the box, the kind used mostly by dressmakers.'

Melchett stared at her, a faint light of comprehension breading in on him. Miss Marple nodded her head several times eagerly.

'Yes, of course. It seems to me so obvious. She was in her kimono because she was going to try on her new dress, and she went into the front room, and Miss Politt just said something about measurements and put the tape measure round her neck - and then all she'd have to do was to cross it and pull - quite easy, so I've heard. And then of course she'd go outside and pull the door to and stand thee knocking as though she'd just arrived. But the pin shows she'd already been in the house.'

'And it was Miss Politt who telephoned to Spenlow?'

'Yes. From the post office at two-thirty - just when the bus comes and the post office would be empty.'

'Colonel Melchett said, 'But, my dear Miss Marple, why? In heaven's name, why? You can't have a murder without a motive.'

'Well, I think, you know, Colonel Mechett, from all I've heard, that the crime dates from a long time back. It reminds me, you know, of my two cousins, Antony and Gordon. Whatever Antony did always went right for him, and with poor Gordon in was jus t the other way about; race horses went lame, and stocks went down, and property depreciated… As I see it, the two women were in it together.'

'In what?'

'The robbery. Long ago. Very valuable emeralds, so I've heard. The lady's maid and the tweeny. Because one thing hasn't been explained - how, when the tweeny married the gardener, did they have enough money to set up a flower shop?

'The answer is, it was her share of the - the swag, I think is the right expression. Everything she did turned out well. Money made money. But the other one, the lady's maid, must have been unlucky. She came down to being just a village dressmaker. Then they met again. Quite all right at first, I expect, until Mr. Ted Gerard came on the scene.

'Mrs. Spenlow, you see, was already suffering from conscience and was inclined to be emotionally religious. This young man no doubt urged her to 'face up' and to 'come clean,' and I daresay she was strung up to do so. But Miss Politt didn't see it t hat way. All she saw was that she might go to prison for a robbery she had committed years ago. So she made up her mind to put a stop to it all. I'm afraid, you know, that she was always rather a wicked woman. I don't believe she'd have turned a hair if that nice, stupid Mr. Spenlow had been hanged.'

Colonel Melchett said slowly, 'We can - er - verify your theory - up to a point. The identity of the Politt woman with the lady's maid at the Abercrombies', but -'

Miss Marple reassured him. 'It will be all quite easy. She's the kind of woman who will break down at once when she's taxed with the truth. And then, you see, I've got her tape measure. I - er - abstracted it yesterday when I was trying on. When she misses it and thinks the police have got it - well, she's quite an ignorant woman and she'll think it will prove the case against her in some way.'

She smiled at him encouragingly. 'You'll have no trouble, I can assure you.' It was the tone in which his favourite aunt had once assured him that he could not fail to pass his entrance examination into Sandhurst.

And he passed.

Greenshaw's Folly

The two men rounded the corner of the shrubbery. 'Well, there you are,' said Raymond West. 'That's It.'

Horace Bindler took a deep, appreciative breath.

'How wonderful,' he cried. His voice rose in a high screech of aesthetic delight, then deepened in reverent awe. 'It's unbelievable. Out of this world! A period piece of the best.'

'I thought you'd like it,' said Raymond West complacently.

'Like it?' Words failed Horace. He unbuckled the strap of his camera and got busy. 'This will be one of the gems of my collection,' he said happily. 'I do think, don't you, that it's rather amusing to have a collection of monstrosities? The idea came to me one night seven years ago in my bath. My last real gem was in the Campo Santo at Genoa, but I really think this beats it. What's it called?'

'I haven't the least idea,' said Raymond.

'I suppose it's got a name?'

'It must have. But the fact is that it's never referred to round here as anything but Greenshaw's Folly.'

'Greenshaw being the man who built it?'

'Yes. In eighteen sixty or seventy or thereabouts. The local success story of the time. Barefoot boy who had risen to immense prosperity. Local opinion is divided as to why he built this house, whether it was sheer exuberance of wealth or whether it was done to impress his creditors. If the latter, it didn't impress them. He either went bankrupt or the next thing to it. Hence the name, Greenshaw's Folly.'

Horace's camera clicked. 'There,' he said in a satisfied voice. 'Remind me to show you Number Three-ten in my collection. A really incredible marble mantelpiece in the Italian manner.' He added, looking at the house, 'I can't conceive of how Mr. Greenshaw thought of it all.'

'Rather obvious in some ways,' said Raymond. 'He had visited the chateaux of the Loire, don't you think? Those turrets. And then, rather unfortunately, he seems to have travelled in the Orient. The influence of the Taj Mahal is unmistakable. I rather like the Moorish wing,' he added, 'and the traces of a Venetian palace.'

'One wonders how he ever got hold of an architect to carry out these ideas.'

Raymond shrugged his shoulders.

'No difficulty about that, I expect,' he said. 'Probably the architect retired with a good income for life while poor old Greenshaw went bankrupt.'

'Could we look at it from the other side?' asked Horace, 'or are we trespassing?'

'We're trespassing all right,' said Raymond, 'but I don't think it will matter.'