'So therefore, if I was to go by you, all the things that seemed to be true were only illusions. Illusions created for a definite purpose - in the same way that conjurers create illusions, to deceive an audience. We were the audience.

'Alex Restarick got an inkling of the truth first because he had the chance of seeing things from a different angle - from the outside angle. He was with the Inspector in the drive, and he looked at the house and realized the possibilities of the windows - and he remembered the sound of running feet he had heard that night, and then the timing of the constable showed him what a very short time things take to what we should imagine they would take. The constable panted a lot, and later, thinking of a puffing constable, I remembered that Lewis Serrocold was out of breath that night when he opened the study door. He'd just been running hard, you see.

'But it was Edgar Lawson that was the pivot of it all to me. There was always something wrong to me about Edgar Lawson. All the things he said and did were exactly right for what he was supposed to be, but he himself wasn't right. Because he was actually a normal young man playing the part of a schizophrenic - and he was always, as it were, a little larger than life. He was always theatrical.

'It must have all been very carefully planned and thought out. Lewis must have realized on the occasion of Christian's last visit that something had aroused his suspicions. And he knew Christian well enough to know that if he suspected he would not rest until he had satisfied himself that his suspicions were either justified or unfounded.' Carrie Louise stirred.

'Yes,' she said. 'Christian was like that. Slow and painstaking, but actually very shrewd. I don't know what it was aroused his suspicions but he started investigating - and he found out the truth.' The Bishop said: 'I blame myself for not having been a more conscientious trustee.' 'It was never expected of you to understand finance,' said Carrie Louise. 'That was originally Mr Gilfoy's province. Then, when he died, Lewis's great experience put him in what amounted to complete control. And that, of course, was what went to his head.' The pink colour came up in her cheeks.

'Lewis was a great man,' she said. 'A man of great vision, and a passionate believer in what could be accomplished - with money. He didn't want it for himself - or at least not in the greedy vulgar sense - he did want the power of it - he wanted the power to do great good with it ' 'He wanted,' said the Bishop, 'to be God.' His voice was suddenly stem. 'He forgot that man is only the humble instrument of God's will.' 'And so he embezzled the Trust funds?' said Miss Marple.

Dr Galbraith hesitated.

'It wasn't only that…' 'Tell her,' said Carrie Louise. 'She is my oldest friend.' The Bishop said: 'Lewis Serrocold was what one might call a financial wizard. In his years of highly technical accountancy, he had amused himself by working out various methods of swindling which were practically foolproof. This had been merely an academic study, but when he once began to envisage the possibilities that a vast sum of money could encompass, he put these methods into practice.

You see, he had at his disposal some first-class material.

Amongst the boys who passed through here, he chose out a small select band. They were boys whose bent was naturally criminal, who loved excitement and who had a very high order of intelligence. We've not got nearly to the bottom of it all, but it seems clear that this esoteric circle was secret and specially trained and were later placed in key positions, where, by carrying out Lewis's directions, books were falsified in such a way that large sums of money were converted without any suspicion being aroused. I gather that the operations and the ramifications are so complicated that it will be months before the auditors can Unravel it all. But the net result seems to be that under various names and banking accounts and companies Lewis Serrocold would have been able to dispose of a colossal sum with which he intended to establish an overseas colony for a cooperative experiment in which juvenile delinquents should eventually own this territory and administer it. It may have been a fantastic dream ' 'It was a dream that might have come true,' said Carrie Louise.

'Yes, it might have come true. But the means Lewis Serrocold adopted were dishonest means, and Christian Gulbrandsen discovered that. He was very upset, particularly by the realization of what the discovery and the probable prosecution of Lewis would mean to you, Carrie Louise.' 'That's why he asked me if my heart was strong, and seemed so worried about my health,' said Carrie Louise.

'I couldn't understand it.' 'Then Lewis Serrocold arrived back from the North and Christian met him outside the house and told him that he knew what was going on. Lewis took it calmly, I think. Both men agreed they must do all they could to spare you. Christian said he would write to me and ask me to come here, as a co-trustee, to discuss the position.' 'But of course,' said Miss Marple, 'Lewis Serrocold had already prepared for this emergency. It was all planned. He had brought the young man who was to play the part of Edgar Lawson to the house. There was a real Edgar Lawson - of course - in case the police looked up his record. This false Edgar knew exactly what he had to do - act the part of a schizophrenic victim of persecution - and give Lewis Serrocold an alibi for a few vital minutes.

'The next step had been thought out too. Lewis's story that you, Carrie Louise, were being slowly poisoned when one actually came to think of it there was only Lewis's story of what Christian had told him - that, and a few lines added on the typewriter whilst he was waiting for the police. It was easy to add arsenic to the tonic. No danger for you there - since he was on the spot to prevent you drinking it. The chocolates were just an added touch - and of course the original chocolates weren't poisoned - only those he substituted before turning them over to Inspector Curry.' 'And Alex guessed,' said Carrie Louise.

'Yes - that's why he collected your nail parings. They would show if arsenic actually had been administered over a long period.' 'Poor Alex - poor Ernie.' There was a moment's silence as the other two thought of Christian Gulbrandsen, of Alexis Restarick, and of the boy Ernie - and of how quickly the act of murder could distort and deform.

'But surely,' said the Bishop, 'Lewis was taking a big risk in persuading Edgar to be his accomplice - even if he had some hold over him -'

Carrie shook her head.

'It wasn't exactly a hold over him. Edgar was devoted to Lewis.'

'Yes,' said Miss Marple. 'Like Leonard Wylie and his father. I wonder perhaps if-'

She paused delicately.

'You saw the likeness, I suppose?' said Carrie Louise.

'So you knew that all along?'

'I guessed. I knew Lewis had once had a short infatuation for an actress, before he met me. He told me about it. It wasn't serious, she was a gold-digging type of woman and she didn't care for him, but I've no doubt at all that Edgar was actually Lewis's son…'

'Yes,' said Miss Marple. 'That explains everything…' 'And he gave his life for him in the end,' said Carrie Louise. She looked pleadingly at the Bishop. 'He did, you knOW.'

There was a silence and then Carrie Louise said: 'I'm glad it ended that way…, with his life given in the hope of saving the boy… People who can be very good can be very bad, too. I always knew that was true about Lewis… But - he loved me very much - and I loved him.'

'Did you - ever suspect him?' asked Miss Marple.

'No,' s,aid Carrie Louise. 'Because I was puzzled by the poisoning. I knew Lewis would never poison me and yet that letter of Christian's said definitely that someone was poisoning me - so I thought that everything I thought I knew about people must be wrong…'