Cordelia never knew how long the tall figure in the red dressing-gown had been watching and listening in the shadow of the door. She never knew how much Miss Learning had heard or at what moment she had stolen quietly away. But now she was aware of the red shadow moving soundlessly over the carpet, eyes, on the figure behind the desk, the gun held closely against her breast. Cordelia watched in fascinated horror, not breathing. She knew exactly what was going to happen. It must have taken less than three seconds but they passed as slowly as minutes. Surely there had been time to cry out, time to warn, time to leap forward and wrench the gun from that steady hand? Surely there had been time for him to cry out? But he made no sound. He half rose, incredulous, and gazed at the muzzle in blind disbelief. Then he turned his head towards Cordelia as if in supplication. She would never forget that last look. It was beyond terror, beyond hope. It held nothing but the blank acceptance of defeat.

It was an execution, neat, unhurried, ritually precise. The bullet went in behind the right ear. The body leapt into the air, shoulders humped, softened before Cordelia's eyes as if the bones were melting into wax, and lay discarded at last over the desk. A thing; like Bernie; like her father.

Miss Learning said:

'He killed my son.'

'Your son?'

'Of course. Mark was my son. His son and mine. I thought you might have guessed.'

She stood with the gun in her hand gazing with expressionless eyes through the open window to the lawn. There was no sound. Nothing moved. Miss Learning said:

'He was right when he said that no one could touch him. There was no proof.'

Cordelia cried out appalled:

'Then how could you kill him? How could you be so sure?'

Without releasing her hold on the pistol, Miss Learning put her hand into the pocket of her dressing-gown. The hand moved over the desk top. A small gilt cylinder rolled over the polished wood towards Cordelia, then rocked into stillness. Miss Learning said:

'The lipstick was mine. I found it a minute ago in the pocket of his dress suit. He hadn't worn that suit since he last dined in Hall on Feast night. He was always a magpie. He put small objects instinctively into his pockets.'

Cordelia had never doubted Sir Ronald's guilt but now every nerve was desperate for reassurance.

'But it could have been planted there! Lunn could have put it there to incriminate him.'

'Lunn didn't kill Mark. He was in bed with me at the time Mark died. He only left my side for five minutes and that was to make a telephone call shortly after eight o'clock.'

'You were in love with Lunn!'

'Don't look at me like that! I only loved one man in my life and he's the one I've just killed. Talk about things you understand. Love had nothing to do with what Lunn and I needed from each other.'

There was a moment's silence. Then Cordelia said:

'Is there anyone in the house?'

'No. The servants are in London. No one is working late at the lab tonight.'

And Lunn was dead. Miss Learning said with weary resignation:

'Hadn't you better phone the police?' 'Do you want me to?' 'What does it matter?'

'Prison matters. Losing your freedom matters. And do you really want the truth to come out in open court? Do you want everyone to know how your son died and who killed him? Is that what Mark himself would want?'

'No. Mark never believed in punishment. Tell me what I have to do.'

'We've got to work quickly and plan carefully. We have to trust each other and we have to be intelligent.' 'We are intelligent. What must we do?'

Cordelia took out her handkerchief and dropping it over the gun, took the weapon from Miss Learning and placed it on the desk. She grasped the woman's thin wrist and pushed her protesting hand against Sir Ronald's palm, pulling against the instinctive recoil, forcing the stiff but living fingers against the soft unresisting hand of the dead.

'There may be firing residue. I don't really know much about that, but the police may test for it. Now wash your hands and get me a pair of thin gloves. Quickly.'

She went without a word. Left alone, Cordelia looked down at the dead scientist. He had fallen with his chin against the desk top and his arms swinging loosely at his sides, an awkward, uncomfortable-looking pose which gave him the appearance of peering malevolently over his desk. Cordelia could not look at his eyes, but she was conscious of feeling nothing, not hatred, or anger, or pity. Between her eyes and the sprawled figure swung an elongated shape, head hideously crooked, toes pathetically pointed. She walked over to the open window and looked out over the garden with the casual curiosity of a guest kept waiting in a strange room. The air was warm and very still. The scent of roses came in waves through the open window, alternately sickening sweet and then as elusive as a half-caught memory.

This curious hiatus of peace and timelessness must have lasted less than half a minute. Then Cordelia began to plan. She thought about the Clandon case. Memory pictured herself and Bernie, sitting astride a fallen log in Epping Forest and eating their picnic lunch. It brought back the yeasty smell of fresh rolls, butter and tangy cheese, the heavy fungoid smell of summer woods. He had rested the pistol on the bark between them and had mumbled at her through the bread and cheese. 'How would you shoot yourself behind the right ear? Go on, Cordelia – show.'

Cordelia had taken the pistol in her right hand, index finger lightly resting on the trigger, and with some difficulty had strained back her arm to place the muzzle of the gun against the base of the skull. 'Like that?' 'You wouldn't, you know.'Not if you were used to a gun. That's the little mistake Mrs Clandon made and it nearly hanged her. She shot her husband behind the right ear with his service revolver and then tried to fake a suicide. But she pressed the wrong finger on the trigger. If he'd really shot himself behind the right ear he'd have pressed the trigger with his thumb and held the revolver with his palm round the back of the butt. I remember that case well. It was the first murder I worked on with the Super – Inspector Dalgliesh, as he was then. Mrs Clandon confessed in the end.' 'What happened to her, Bernie?' 'Life. She'd probably have got away with manslaughter if she hadn't tried to fake a suicide. The jury didn't much like what they heard about Major Clandon's little habits.'

But Miss Learning couldn't get away with manslaughter; not unless she told the whole story of Mark's death.

She was back in the room now. She handed Cordelia a pair of thin cotton gloves. Cordelia said:

'I think you'd better wait outside. What you don't see you won't have the trouble of forgetting. What were you doing when you met me in the hall?'

'I was getting myself a nightcap, a whisky.'

'Then you would have met me again coming out of the study as you took it up to your room. Get it now and leave the glass on the side table in the hall. That's the kind of detail the police are trained to notice.'

Alone again, Cordelia took up the gun. It was astonishing how repulsive she found this inert weight of metal now. How odd that she should ever have seen it as a harmless toy! She rubbed it thoroughly with the handkerchief erasing Miss Learning's prints. Then she handled it. It was her gun. They would expect to find some of her prints on the butt together with those of the dead man. She placed it again on the desk top and drew on the gloves. This was the more difficult part. She handled the pistol gingerly and took it over to the inert right hand. She pressed his thumb firmly against the trigger, then wound the cold, unresisting hand round the back of the butt. Then she released his fingers and let the gun fall. It struck the carpet with a dull thud. She peeled off the gloves and went out to Miss Learning in the hall, closing the study door quietly behind her.