'Not of you but of myself. I'm frightened of what I'm thinking.'

'So the cottage was empty. What else is there? Obviously there is something else.'

Meg said: 'That message on your answerphone; if you'd really received it at ten past eight you would have telephoned Norwich station and left a message for me to ring back. You knew how much the Copleys disliked the thought of going to their daughter. No one else on the headland knew that. The Copleys never spoke of it and nor did I, not to anyone except you. You would have rung, Alice. There could have been an announcement over the station loudspeaker and I could have driven them home. You would have thought of that.'

Alice said: 'One lie to Rickards which could have been a matter of convenience, a wish to avoid trouble, and one instance of insensitive neglect. Is that all?'

'The knife. The middle knife in your block. It wasn't here. It meant nothing at the time, of course, but the block looked odd. I was so used to seeing the five carefully graded knives, each in its sheath. It's back now. It was back when I called in on the Monday after the murder. But it wasn't here on the Sunday night.'

She wanted to cry out: 'You can't be going to use it! Alice, don't use it!' Instead she made herself go on, trying to keep her voice calm, trying not to plead for reassurance, understanding.

'And next morning, when you telephoned to say that Hilary was dead, I didn't say anything about my visit. I didn't know what to believe. It wasn't that I suspected you; that would have been impossible for me, it still is. But I needed time to think. It was late morning before I could bring myself to come to you.'

'And then you found me here with Chief Inspector Rickards and heard me lying. And you saw that the knife was back in the block. But you didn't speak then and you haven't spoken since, not even, I presume, to Adam Dalgliesh.'

It was a shrewd thrust. Meg said: 'I've told no one, how could I? Not until we'd spoken. I knew that you must have had what seemed to you a good reason for lying.'

'And then, I suppose, slowly, perhaps unwillingly, you began to realize what that reason might be?'

'I didn't think you'd murdered Hilary. It sounds fantastic, ludicrous even to speak those words, to think of suspecting you. But the knife was missing and you weren't there. You did lie and I couldn't understand why. I still can't. I wonder who it is you're shielding. And sometimes – forgive me, Alice – sometimes I wonder whether you were there when he killed her, kept guard, stood there watching, might even have helped him by cutting off her hair.'

Alice sat so still that the long-fingered hands resting in her lap, the folds of her shift, might have been carved in stone. She said: 'I didn't help anyone – and no one helped me. There were only two people on that beach, Hilary Robarts and I. I planned it alone and I did it alone.'

For a moment they sat in silence. Meg felt a great coldness. She heard the words and she knew that they were true. Had she, perhaps, always known? She thought: I shall never be with her in this kitchen again, never again find the peace and security which I found in this room. And there fell into her mind an incongruous memory; herself sitting quietly in the same chair and watching while Alice made short pastry; sieving the flour on to a marble slab, adding the squares of soft butter, breaking in the egg, her long fingers delicately dabbling the mixture, drawing in the flour, lightly forming the glistening ball of dough. She said: 'They were your hands. Your hands tightening the belt round her throat, your hands cutting off her hair, your hands slicing that L into her forehead. You planned it alone and you did it alone.'

Alice said: 'It took courage, but perhaps less than you would imagine. And she died very quickly, very easily. We shall be lucky to go with so little pain. She hadn't even time to feel terror. She had an easier death than most of us can look forward to. And as for what followed, that didn't matter. Not to her. Not even much to me. She was dead. It's what you do to the living that takes the strong emotions, courage, hatred and love.'

She was silent for a moment, then she said: 'In your eagerness to prove me a murderess, don't confuse suspicion with proof. You can't prove any of this. All right, you say the knife was missing, but that's only your word against mine. And if it was missing, I could say that I went for a short walk on the headland and the murderer saw his chance.'

'And put it back afterwards? He wouldn't even know that it was there.'

'Of course he would. Everyone knows that I'm a cook, and a cook has sharp knives. And why shouldn't he put it back?'

'But how would he get in? The door was locked.'

'There's only your word for that. I shall say that I left it open. People on the headland usually do.'

Meg wanted to cry out: 'Don't, Alice. Don't begin planning more lies. Let there at least be truth between us.' She said: 'And the portrait, the smashed window, was that you too?'

'Of course.'

'But why? Why all that complication?'

'Because it was necessary. While I was waiting for Hilary to come out of the sea I glimpsed Theresa Blaney. She suddenly appeared on the very edge of the cliff by the abbey ruins. She was only there for a moment and then she disappeared. But I saw her. She was unmistakable in the moonlight.'

'But if she didn't see you, if she wasn't there when you… when Hilary died…'

'Don't you see? It meant that her father wouldn't have an alibi. She has always struck me as a truthful child and she has had a strict religious upbringing. Once she told the police that she was out on the headland that night Ryan would be in terrible danger. And even if she had sense enough to lie, for how long could she keep it up? The police would be gentle questioning her. Rickards isn't a brute. But a truthful child would find it difficult to lie convincingly. When I got back here after the murder I played back the messages on the answerphone. It occurred to me that Alex might change his plans and telephone. And it was then, too late, that I got George Jago's message. I knew that the murder could no longer be pinned on the Whistler. I had to give Ryan Blaney an alibi. So I tried to ring him to say that I'd collect the picture. When I couldn't get through I knew I had to call at Scudder's Cottage and as quickly as possible.'

'You could just have collected the portrait, knocked at the door to say what you'd done, seen him then. That would be proof enough that he was at home.'

'But it would have looked too deliberate, too contrived. Ryan had made it plain that he didn't want to be disturbed, that I was merely to collect the portrait. He made that very clear. And Adam Dalgliesh was with me when he said it. Not any casual caller, but Scotland Yard's most intelligent detective. No, I had to have a valid excuse to knock and speak to Ryan.'

'So you put the portrait in the boot of your car and told him that it wasn't in the shed?' It seemed to Meg extraordinary that horror could briefly be subsumed by curiosity, by the need to know. They might have been discussing complicated arrangements for a picnic.

Alice said: 'Exactly. He was hardly likely to think that it was I who had taken it only a minute earlier. It was convenient, of course, that he was half drunk. Not as drunk as I described to Rickards, but obviously incapable of killing Robarts and getting back to Scudder's Cottage by a quarter to ten.'

'Not even in the van or on his bicycle?'

'The van was out of commission and he couldn't have stayed on the bicycle. Besides, I would have passed him cycling home. My evidence meant that Ryan would be safe even if Theresa confessed that she'd left the cottage. After I left him I drove back over a deserted headland. I stopped briefly below the pillbox and threw the shoes inside. I had no way of burning them except on an open fire where I had burned the paper and string from the wrapped portrait, but I had an idea that burning rubber could leave some trace and a persistent smell. I didn't expect the police to search for them because I didn't believe they would find a print. But even if they did there would be nothing to link those particular shoes with the murder. I washed them thoroughly under the outside tap before I disposed of them. Ideally I could have returned them to the jumble box but I daren't wait and that night I knew that, with you gone to Norwich, the back door would be locked.'