'He asked me about Mrs Serrocold's health. In particular, about her heart.' 'Her heart? Is there something wrong with her heart?' 'Nothing whatever, I understand.' Inspector Curry was silent for a moment or two, then he said: 'You heard a shot this evening during the quarrel between Mr Serrocold and Edgar Lawson?' 'I didn't actually hear it myself. I am a little deaf, you know. But Mrs Serrocold mentioned it as being outside in the park.' 'Mr Gulbrandsen left the party immediately after dinner, I understand?' 'Yes, he said he had letters to write.' 'He didn't show any wish for a business conference with Mr Serrocold?' 'No.' Miss Marple added: 'You see, they'd already had one little talk.'

'They had? When? I understood that Mr Serrocold only returned home just before dinner.' 'That's quite true, but he walked up through the park, and Mr Gulbrandsen went out to meet him and they walked up and down the terrace together.' 'Who else knows this?' 'I shouldn't think anybody else,' said Miss Marple.

'Unless, of course, Mr Serrocold told Mrs Serrocold. I just happened to be looking out of my window - at some birds.' 'Birds?' 'Birds,' Miss Marple added after a moment or two: 'I thought, perhaps, they might be siskins.' Inspector Curry was uninterested in siskins.

'You didn't,' he said delicately, 'happen to - er overhear anything of what they said?' Innocent china blue eyes met his.

'Only fragments, I'm afraid,' said Miss Marple gently.

'And those fragments?' Miss Marple was silent for a moment, then she said: 'I do not know the actual subject of their conversation, but their immediate concern was to keep whatever it was from the knowledge of Mrs Serrocold. To spare her - that was how Mr Gulbrandsen put it, and Mr Serrocold said, "I agree that it is she who must be considered." They also mentioned a "big responsibility" and that they should, perhaps, "take outside advice."' She paused.

'I think you know, you had better ask Mr Serrocold himself about all this.' 'We shall do so, m'am. Now there is nothing else that struck you as unusual this evening?' Miss Marple considered.

'It was all so unusual if you know what I mean ' 'Quite so. Quite so.' Something flickered into Miss Marple's memory.

'There was one rather unusual incident. Mr Serrocold stopped Mrs Serrocold from taking her medicine. Miss Bellever was quite put out about it.' She smiled in a deprecating fashion.

'But that, of course, is such a little thing…' 'Yes, of course. Well, thank you, Miss Marple.' As Miss Marple went out of the room, Sergeant Lake said: 'She's old, but she's sharp…'

Lewis Serrocold came into the office and immediately the whole focus of the room shifted. He turned to close the door behind him, and in doing so he created an atmosphere of privacy. He walked over and sat down, not in the chair Miss Marple had just vacated, but in his own chair behind the desk. Miss Bellever had settled Inspec-tor Curry in a chair drawn up to one side of the desk, as though unconsciously she had reserved Lewis Serro-cold's chair against his coming.

When he had sat down, Lewis Serrocold looked at the two police officers thoughtfully. His face looked drawn and tired. It was the face of a man who was passing through a severe ordeal, and it surprised Inspector Curry a little because, though Christian Gulbrandsen's death must undeniably have been a shock to Lewis Serrocold, yet Gulbrandsen had not been a close friend or relation, only a rather remote connection by marriage.

In an odd way, the tables seemed to have been turned.

It did not seem as though Lewis Serrocold had come into the room to answer police questioning. It seemed rather that Lewis Serrocold had arrived to preside over a court of inquiry. It irritated Inspector Curry a little.

He said briskly:

'Now, Mr Serrocold -'

Lewis Serrocold still seemed lost in thought. He said with a sigh: 'How difficult it is to know the right thing to do.' Inspector Curry said: 'I think we will be the judges of that, Mr Serrocold.

Now about Mr Gulbrandsen, he arrived unexpectedly, I understand?' 'Quite unexpectedly.' 'You did not know he was coming.' 'I had not the least idea of it.' 'And you have no idea of why he came?' Lewis Serrocold said quietly: 'Oh yes, I know why he came. He told me.' 'When?' 'I walked up from the station. He was watching from the house and came out to meet me. It was then that he explained what had brought him here.' 'Business connected with the Gulbrandsen Institute, I suppose?' 'Oh no, it was nothing to do with the Gulbrandsen Institute.' 'Miss Bellever seemed to think it was.' 'Naturally. That would be the assumption. Gulbrandsen did nothing to correct that impression. Neither did I.' 'Why, Mr Serrocold?' Lewis Serrocold said slowly: 'Because it seemed to both of us important that no hint should arise as to the real purpose of his visit.' 'What was the real purpose?' Lewis Serrocold was silent for a minute or two. He sighed.

'Gulbrandsen came over here regularly twice a year for meetings of the trustees. The last meeting was only a month ago. Consequently he was not due to come over again for another five months. I think, therefore, that anyone might realize that the business that brought him must definitely be urgent business, but I still think that the normal assumption would be that it was a business visit, and that the matter, however urgent - would be a Trust matter. As far as I know, Gulbrandsen did nothing to contradict that impression - or thought he didn't. Yes, perhaps that is nearer the truth - he thought he didn't.' 'I'm afraid, Mr Serrocold, that I don't quite follow you.' Lewis Serrocold did not answer at once. Then he said gravely: 'I fully realize that with Gulbrandsen's death - Which was murder, undeniably murder, I have got to put all the facts before you. But frankly, I am concerned for my wife's happiness and peace of mind. It is not for me to dictate to you, Inspector, but if you can see your way to keeping certain things from her as far as possible I shall be grateful. You see, Inspector Curry, Christian Gulbrandsen came here expressly to tell me that he believed my wife was being slowly and cold-bloodedly poisoned.' 'What?' Curry leaned forward incredulously.

Serrocold nodded.

'Yes, it was, as you can imagine, a tremendous shock to me. I had had no suspicion of such a thing myself, but as soon as Christian told me, I realized that certain symptoms my wife had complained of lately were quite compatible with that belief. What she took to be rheumatism, leg cramps, pain, and occasional sickness.

All that fits in very well with the symptoms of arsenical poisoning.' 'Miss Marple told us that Christian Gulbrandsen asked her about the condition of Mrs Serrocold's heart.' 'Did he now? That's interesting. I suppose he thought that a heart poison would be used since it paved the way to a sudden death without undue suspicion. But I think myself that arsenic is more likely.' 'You definitely think, then, that Christian Gulbrandsen's suspicions were well founded?' 'Oh yes, I think so. For one thing, Gulbrandsen would hardly come to me with such a suggestion unless he was fairly sure of his facts. He was a cautious and hardheaded man, difficult to convince, but very shrewd.' 'What was his evidence?' 'We had no time to go into that. Our interview was a hurried one. It served only the purpose of explaining his visit, and a mutual agreement that nothing whatever should be said to my wife about the matter until we were sure of our facts.' 'And whom did he suspect of administering poison?' 'He did not say, and actually I don't think he knew. He may have suspected. I think now that he probably did suspect - otherwise why should he be killed?' 'But he mentioned no name to you?' 'He mentioned no name. We agreed that we must investigate the matter thoroughly, and he suggested inviting the advice and co-operation of Dr Galbraith, the Bishop of Cromer. Dr Galbraith is a very old friend of the Gulbrandsens and is one of the trustees of the Institute.