‘We are as sure as we can be that we are the only people in the house, as of this moment in time. We are also sure that the curtains and dishes and so on in the dining-room were tampered with. And that is all we are sure of.

‘We do not know who did this or why.

‘It is possible that it was done by someone who was concealed in the house – Mr Wilson’s man? – and has now left, or by one or more of us. If it was us, then the only candidates are Dr Bourne, Miss Parish and Miss Mair who were the last to come to the lounge this afternoon, or Dr Meredith and Miss Parish, who left the lounge before us and ostensibly discovered the rearrangement.’

Meredith, about to speak, was forestalled by Bourne.

‘I follow your argument, Captain Pollard, and agree entirely. But I really feel it is beyond credibility that Dr Meredith and Ann arranged the dining-room display. It is my recollection that there just was not enough time for them to do so before they asked us to come through.’

‘That’s right,’ said Swanson. ‘I switched off the camera. I remember I just had time enough to note how much film we’d shot when Mr Meredith and Miss Parish came back in.’

Pollard nodded in satisfaction.

‘Good. That’s what I felt but I wanted to hear it from you, too. Which,’ he added slowly, ‘brings us to Dr Bourne, Miss Parish and Miss Mair.’

‘There wasn’t time.’ Paul found himself quite sure of that. ‘Think about it, Pollard. Think of what we talked about when we came in here after lunch. There just was not enough time for Ann and Joyce, with or without Dr Bourne’s help, to set up the dining-room.’

There was silence. He held Pollard’s grey eyes for a long moment. The army man sighed.

‘All right. I agree . . . So where does that leave us?’

Jeremy Hunt stirred.

‘We’re back to Mr Wilson’s intruder, surely? He must be a nut-case. Maybe a tramp who was sleeping in the house heard us arrive, lay low and then . . .’ He broke off, shrugged. ‘Doesn’t seem likely, does it?’

Meredith spoke for the first time.

‘Mr Wilson, are you absolutely sure you saw a man at the upstairs window?’

Startled, Paul recalled the scene.

‘Of course I did. The light was good. I saw him distinctly.’

‘You could not have been mistaken?’

‘No, absolutely not.’

Meredith did not pursue the matter. But Bourne did, a glint of understanding in his sharp eyes.

‘Are you thinking Mr Wilson was hallucinating?’

Meredith nodded slowly.

Paul felt annoyance flare within him.

‘Hallucinating! Look, I am not subject to hallucinations!’

Meredith made smoothing-down gestures.

‘No, no, Mr Wilson, you misunderstand me. I don’t mean “hallucinations” in the normal way.’

‘Hallucinations in the normal way?’ Jeremy Hunt grinned. ‘Surely it’s abnormal for anyone to suffer hallucinations?’