As if it were inevitable, the Scots voice informed me, 'He was killed in Dorothea's house... with a knife.'

I sighed; a groan. 'Does Dorothea know?'

'The police sent a policewoman to the hospital.'

'Poor, poor Dorothea.'

He said bluntly, 'She won't be bullied any more.'

'But she loved him,' I protested. 'She loved the baby he'd been. She loved her little son. She will be devastated.'

'Go and see her,' Robbie said. 'You seem to understand her. I never could see why she put up with him.'

She needed a hug, I thought. She needed someone to hold her while she wept. I said, 'What about Paul's wife, Janet?'

'The police have told her. She's on her way here now, I think.'

I looked at my watch. Five past seven. I was sore and hungry and had tomorrow's shots to discuss with Nash and Moncrieff. Still...

'Robbie,' I said, 'does Professor Derry have an address?'

'There's a phone number.' He read it out. 'What about Dorothea?'

'I'll go to see her now. I could be at the hospital in about forty minutes. Can you fix it that they'll let me see her?'

He could and would. Who had discovered Paul's murder, I asked.

'I did, d.a.m.n it. At about three o'clock this afternoon I went to pick up a notebook that I left in Dorothea's kitchen last night. I called to get the key again from her friend Betty, but she said she didn't have the key any more, she'd given it to Paul this morning early. I went across to Dorothea's house and rang the bell that ruddy quiet ding-dong and no one came, so I went round the back and tried the kitchen door, and it was open.' He paused. 'Paul was lying in the hall on almost the exact spot where Betty found Dorothea. There wasn't any blood, though. He'd died at once and he'd been dead for hours. He was killed with what looked like one of Dorothea's big kitchen knives. It was still in him, driven deep into his chest from behind at a point not far above his right elbow...

'Robbie,' I said, stunned.

'Yes. Almost the same place as you. The handle was sticking out. An ordinary chef's knife handle, nothing fancy. No Fury. So I phoned the police and they kept me hanging about in that house all afternoon, but I couldn't tell them why Paul had gone there. How could I know? I couldn't tell them anything except that it looked to me as if the knife had reached his heart and stopped it.'

I cleared my throat. 'You didn't tell them about... me?'

'No. You didn't want me to, did you?'

'I did not.'

'But things are different now,' he said dubiously.

'Not if the police find Paul's killer quickly.'

'I've got the impression that they don't know where to look. They'll be setting up an incident room, though. There will be all sorts of questions. You'd better be ready for them, because you were there in that house after Dorothea was attacked, and they have your fingerprints.'

'So they have.' I thought a bit and asked, 'Is it against the law not to report having a knife stuck into you?'

'I don't really know,' Robbie said, 'but I know it's mostly against the law to carry a knife like the Fury in a public place, which is what O'Hara did when the two of you took it away with you last night. He could be liable for a fine and six months in jail.'

'You're kidding?'

'No. There are fierce laws now about carrying offensive weapons, and you can't get anything much more offensive than a Fury.'

'Forget you ever saw it.'

'So easy.'

We had cleaned the kitchen the evening before by bundling the body protectors, my shirt, my sweater and Robbie's medical debris into a trash bag, knotting the top; and we'd taken it with us, casually adding it to the heap of similar bags to one side of Bedford Lodge, from where mountains of rubbish and empty bottles were cleared daily.

Robbie in farewell said again he would tell the nurses it was OK to let me in to see Dorothea, and asked me to phone him back later.

Promising I would, I said goodbye to him and dialled the number of Professor Meredith Derry who, to my relief, could be brought to the phone and who would acquiesce to a half-hour's worth of knife-expertise, especially if I were paying a consultancy fee.

'Of course,' I said heartily. 'Double, if it can be this evening.'

'Come when you like,' the Professor said, and gave me an address and directions.

Dorothea's grief was as deep and pulverising as I'd feared. The tears flowed the minute she saw me, weak endless silent tears, not howls and sobs of pain, but an intense mourning as much for times past as for present loss.

I put my arm round her for a while and then simply held her hand, and sat there in that fashion until she fumbled for a tissue lying on the bed and weakly blew her nose.

'Thomas.'

'Yes, I know. I'm so sorry.'

'He wanted what was best for me. He was a good son.'

'Yes,' I said.

'I didn't appreciate him enough...'

'Don't feel guilty,' I said.

'But I do. I can't help it. I should have let him take me with him as soon as Valentine died.'

'No,' I said. 'Stop it, dearest Dorothea. You are not to blame for anything. You mustn't blame yourself.'

'But why? why? Why would anyone want to kill my Paul?' Why would anyone want to kill my Paul?'

'The police will find out.'

'I can't bear bear it.' The tears came again, preventing speech. it.' The tears came again, preventing speech.

I went out of her room to ask the nurses to give Dorothea a sedative. She had already been given one. No more without a doctor's say-so, they said.

'Then get a doctor,' I told them irritably. 'Her son's been murdered. She's feeling guilty.'

'Guilty? Why?'

It was too difficult to explain. 'She will be seriously ill by morning if you don't do something.'

I went back to Dorothea thinking I'd wasted my breath, but ten minutes later one of the nurses came in brightly and gave her an injection, which almost immediately sent her to sleep.

'That satisfy you?' the nurse asked me with a hint of sarcasm.

'Couldn't be better.'

I left the hospital and helped my driver find the way to Professor Derry. The driver was on time-and-a-half for evening work and said he was in no hurry at all to take me home.

Professor Derry's retirement was no gold-plated affair. He lived on the ground floor of a tall house divided horizontally irto flats, himself occupying, it transpired, a study, a bedroom, a bathroom and a screened-off kitchen alcove, all small and heavy-looking in brown wood, all the fading domain of an ancient academic living frugally.

He was white haired, physically stooped and frail, but with eyes and mind in sharp array. He waved me into his study, sat me down on a wooden chair with arms and asked how he could help.

'I came for information about knives.'

'Yes, yes,' he interrupted. 'You said that on the phone.'

I looked around but could see no phone in his room. There had, however, been one a pay phone out in the hallway, shared with the upstairs tenants.

I said, 'If I show you a drawing of a knife, could you tell me about it?'

'I can try.'

I took the drawing of the Heath knife out of my jacket pocket and handed it to him folded. He opened it, flattened it out and laid it aside on his desk.

'I have to tell you,' he said with many small, rapid lip movements, 'that I have recently already been consulted about a knife like this.'

'You are an acknowledged expert, sir.'

'Yes.' He studied my face. 'Why do you not ask who consulted me? Have you no curiosity? I don't like students who have no curiosity.'

'I imagine it was the police.'

The old voice cackled in a wheezy sort of laugh. 'I see I have to rea.s.sess.'

'No, sir. It was I who found the knife on Newmarket Heath. The police took it into custody. I didn't know they had consulted you. It was curiosity, strong and undiluted, that brought me here.'

'What did you read?'

'I never went to university.'

'Pity.

'Thank you, sir.'

'I was going to have some coffee. Do you want some coffee?'

'Yes. Thank you, I'd like some.'

He nodded busily, pulled aside the screen, and in his kitchen alcove heated water, spooned instant powder into cups and asked about milk and sugar. I stood and helped him, the small domesticity a signal of his willingness to impart.

'I didn't care for the two young policemen who came here,' he said unexpectedly. 'They called me Granddad. Patronising.'

'Stupid of them.'

'Yes. The sh.e.l.l grows old, but not the inhabiting intellect. People see the sh.e.l.l and call me Granddad. And Dearie Dearie. What do you think of Dearie? Dearie?'

'I'd kill 'em.'

'Quite right.' He cackled again. We carried the cups across to the chairs. 'The knife the police brought here,' he said, 'is a modern replica of a trench knife issued to American soldiers in France in the First World War.'

'Wow,' I said.

'Don't use that ridiculous word.'

'No, sir.'

'The policemen asked why I thought it was a replica and not tne real thing. I told them to open their eyes. They didn't like it.'

'Well... er... how did you know?'

He cackled. 'It had "Made in Taiwan" stamped into the metal. Go on, say it.'

I said, 'Taiwan wasn't called Taiwan in World War One.'

'Correct. It was Formosa. And at that point in its history, it was not an industrial island.' He sat and tasted his coffee, which, like mine, was weak. 'The police wanted to know who owned the knife. How could I possibly know? I said it wasn't legal in England to carry such a knife in a public place, and I asked where they had found it.'

'What did they say?'

'They didn't. They said it didn't concern me. Granddad.'

I told him in detail how the police had acquired their trophy and he said, mocking me, 'Wow.'

I was becoming accustomed to him and to his crowded room, aware now of the walls of bookshelves, so like Valentine's, and of his cluttered old antique walnut desk, of the single bra.s.s lamp with green metal shade throwing inadequate light, of rusty-green velvet curtains hanging from great brown rings on a pole, of an incongruously modern television set beside a worn old typewriter, of dried faded hydrangeas in a cloisonne vase and a bra.s.s roman-numeralled clock ticking away the remains of a life.

The room, neat and orderly, smelled of old books, of old leather, of old coffee, of old pipe smoke, of old man. There was no heating, despite the chilly evening. An old three-barred electric fire stood black and cold. The professor wore a sweater, a scarf, a shabby tweed jacket with elbow patches, and indoor slippers of brown checked wool. Bifocals gave him sight, and he had meticulously shaved: he might be old and short of cash, but standards had nowhere slipped.

On the desk, in a silver frame, there was an indistinct old photograph of a younger himself standing beside a woman, both of them smiling.

'My wife,' he explained, seeing where I was looking. 'She died.'

'I'm sorry.'

'It happens,' he said. 'It was long ago.'

I drank my unexciting coffee, and he delicately brought up the subject of his fee.

'I haven't forgotten,' I said, 'but there's another knife I'd like to ask you about.'