'Go on.'

'Well, I was worried about her. It's as simple as that. Nothing I'd heard from Alice had reassured me. And I couldn't get Sally to speak to me on the phone. So, I went to Hampstead to see her. As it turned out, I never got to Alice's house. I spotted Sally sitting in a coffee shop near the Tube station. This was about… ten o'clock in the morning. I went in and tried to talk to her. It didn't go well. Truth is, her attitude annoyed me. Stupid of me to let it happen. Very unprofessional. But there it is. I asked her about the broken appointment and she just dismissed the subject. "Something else cropped up." That was her answer. Which made no sense, obviously. Then I spotted the magazine she'd been reading. It was from my waiting room. My PLEASE DO NOT REMOVE STICKER was still on the cover. That riled me. Such a petty thing, too. Anyway, I asked if and when she was planning to return it. I must have sounded so pompous. She got up, threw the magazine at me and walked out. "You don't need to worry about me any more," she shouted. Those were the last words she ever spoke to me. I should have realized, of course, what they really meant.'

'Which was?'

'That I needed to worry about her like never before.' Claire rubbed her hands together, then parted them in a gesture of helplessness. 'I'm sorry I let her go like that, David. Sorry I didn't… save her from herself.'

'Don't be.'

'Because it wasn't herself she needed saving from? That won't wash. You know it won't.'

'Maybe something else really had cropped up. Maybe something else is why she was murdered.'

'The truth about what happened at Avebury twenty-three years ago?'

'Exactly.'

'Don't you think Oliver Hall would have uncovered that, given the lengths he went to?'

'Sally told you about the private detective he employed, did she?'

Claire frowned. 'No. How could she?'

'We're taking about Alan Wisby, right? The guy Oliver Hall hired when he gave up on the police investigation. The guy who came out to Barcelona to question Sally and me.'

Claire was still frowning. 'Wisby was his name, yeah. But he came to see me a few months after Sally's death.'

'He did?'

'Yes. I had no idea he'd been working for Hall from way back. He never said so.'

'But he did say he was working for Hall then?'

'Yes. He explained that Oliver Hall wanted to find out why Sally had killed herself in case it had some bearing on his daughters' deaths.'

Wisby had still been on the trail five years ago. That meant Oliver Hall had been on the trail. Why would he have been? He had claimed only yesterday to have accepted Radd's guilt long since. Had Sally been in contact with him, despite his assurances to the contrary? 'What did you tell Wisby?' Umber asked, hastening to catch up with the lie he had caught Hall out in.

'Nothing. I don't discuss my clients with passing strangers. I'm only discussing Sally with you because you were married to her.'

'So you gave Wisby the brush-off?'

'I told him his employer had no reason to enquire into the matter.'

'Wisby accepted that?'

'He asked a few questions. When he realized he wasn't going to get anywhere, he gave up and left.'

'What sort of questions?'

'He wanted to know what had been on Sally's mind in the months before her death. He quoted a name at me. Asked if Sally had mentioned it. Well, she hadn't and I said so. It seemed the easiest way to get rid of him.'

'What was the name?'

'Gosh, I can't remember now. Somebody linked with the Avebury case, I suppose. I didn't recognize it.'

'Nevinson?'

'He was the other witness, right? No. That wasn't it.'

'Collingwood?'

'No.'

'Sharp?'

'The policeman? No.'

Umber hesitated, then threw out one more name, sure in his own mind of the answer Claire would give. 'Griffin?'

'Yes,' she said, confounding him. 'That was it.'

Half an hour later Umber was walking fast along South Street. The probable futility of his journey to Mayfair had not restrained him. He stood a better chance of finding Oliver Hall at home in the evening, but he could not wait till then. He knew himself well enough to understand that he could not return to the British Library without first trying his luck at Kingsley House.

He recited to himself as he went the multiplying significances of what Claire Wheatley had told him. Oliver Hall did not believe Radd had killed his daughters. He did not believe Sally had killed herself. He did not even believe both of his daughters were necessarily dead. Wisby had been working for him all these years: probing, enquiring, ever seeking the answer. And the answer had something to do with Griffin.

'Yes?' It was Marilyn's voice, responding just when Umber had convinced himself there would be no answer.

'David Umber here.'

'David?'

'Yes.'

There was a fraction of a second's pause. Then the door-release buzzed.

The door of the flat was ajar, as before, and the warmth had been restored to it. The music was back, more wallpapery this time, soothingly electronic. Marilyn walked along the passage from the bedrooms to greet him, towelling her hair as she came. She was wearing fluffy mules and a peach-coloured dressing gown, belted at the waist. The material of the gown was soft and clinging. She did not look to be wearing anything beneath.

'This is a surprise,' she said. 'I thought you'd wait till Thursday.'

'I was looking for your husband.'

'In banking hours? Here?'

'Sorry if I… disturbed you.'

'That's OK.' She smiled. 'I was just taking a shower. London's such a dirty city, isn't it?'

'Er, yes. Yes, it is.'

'Coffee? Tea? Something stronger?'

'No thanks. I won't stop.'

'That's a pity.'

'When will he be back?'

'Oliver? Hard to say. Six? Seven? I don't know.' She tossed the towel over a radiator and padded past him into the drawing room. He followed, a few paces behind. 'Do you want to leave a message for him? I think we'd better come clean about your visit this time, don't you? We don't want to push our luck.' She caught his gaze in the mirror above the fireplace.

'You could tell him I've found out about Wisby.'

'Who?'

'The private detective he's hired.'

'First I've heard of it. What was the name?'

'Wisby. Alan Wisby.'

'Are you sure about this, David?' She turned to look at him directly. 'How long has this man been working for Oliver?'

'More than twenty years, off and on.'

'And what's he been investigating? Or is that a stupid question?'

'Anything but, given how certain Oliver said he was that Radd was guilty.'

'I see. Well, I'll certainly tell him. Of course, he may deny employing the man.'

'I expect he will.'

'Then, what do you gain by asking him? If he's been using a private detective, he's been doing it without my knowledge. So, he's pretty well certain to deny it. And if he hasn't, he'll deny it anyway. Either way, you won't believe him.'

'I can prove Wisby's been working for him.'

'How?'

'Wisby approached Sally's psychotherapist on Oliver's behalf.'

'Really?'

'Claire Wheatley. She's a disinterested professional. And she was emphatic on the point. Wisby made it clear to her he was working for Oliver.'

'Perhaps he was lying.'

'Somebody's lying.'

'If it's Oliver, he's not likely to stop now. Are you sure you want me to tell him you know about Wisby – assuming there's anything to know?'

Suddenly, Umber was far from sure. Marilyn's casual cynicism regarding her husband's honesty was strangely disarming.