There was a dressing table in the corner, this time littered with torn pieces of wrappers, some face powder and the smudge marks of spilled liquids. There was a large plastic box on the bed. I opened it carefully and found a set of electric hair-curlers. I closed the lid again and wiped the places I'd touched. A waste-paper basket held a collection of plastic bottles: shampoo, moisturizing cream, hair conditioner, hair colouring and a lot of screwed-up tissues and tufts of cotton wool. There was more evidence of occupation in the bathroom: long hairs in the bath where someone – probably a woman -had washed her hair, and towels draped unfolded on the rack so that they would dry easily.

'That's right,' said Werner. 'It's not like a weekend cottage; it's like a safe house.' He followed me downstairs. I looked round the kitchen. 'Did you discover where the booze is kept when you first got in?'

'There's no booze.'

'Don't be idiotic, Werner. There is always booze in a safe house.'

'There's a bottle of something in the refrigerator.' Werner took a chair and sat astraddle it, leaning his elbow on the chairback, his hand propped under his wide jaw. He watched me, his black eyes glowering under those bushy black eyebrows, and his forehead wrinkled in a disapproving frown. Sometimes I didn't notice what a huge bear of a man he was, but now, his shoulders hunched and his feet spread wide apart, he looked almost like a Sumo wrestler.

He stared at me while I found some glasses in a cabinet and got the drink – a large square-shaped green bottle of Bokma oude jenever – from the refrigerator. It had no doubt come from some sailing trip to the Dutch coast. Still standing, I poured some for myself and one for Werner. He waved it away at first, but when I drank some of mine he picked it up and sniffed it suspiciously before sipping some and pulling a face.

'Poor MacKenzie,' I said. I didn't sit down with him. I went round the room with bottle and glass in my hands, looking at all the pictures, the fittings and the furniture, remembering the time I'd spent here.

'A probationer, was he? He hadn't learned when to be afraid.'

'The black girl was dressed as a nurse. She got a ride in my car. She said she was late for work. She pulled a hypodermic needle on me. The seat belt held me. I felt a bloody fool, Werner. But what could I do?'

'She must have slept in the second bedroom. There is a nurse's uniform in the wardrobe and a box of medical equipment including a couple of hypodermics and some drugs with labels that I don't understand.'

'She said she was from Jamaica. They probably chose her because she has a British passport.' I sat down and put my glass on the table with the bottle.

'Yes, I saw her go through immigration with UK passport holders.'

'But why this house, Werner? If she was a KGB agent, why this departmental safe house? They have their own places, houses we don't know about.'

Werner pulled a face to show me he didn't know the answer.

'I sent MacKenzie off to find her.'

'Looks like he found her,' said Werner.

'You followed the black girl here. What then?'

'I went back to London. Zena was in London, just for two days. I didn't want to leave her on her own. She frets when left alone.'

'You're a bloody wonderful agent, Werner.'

'I didn't know it was important,' said Werner. His flushed face and the anger in his voice were indications of embarrassment. 'How could I guess it was going to turn out like this?'

'But you came back. Then what?'

'The black girl's car had gone. I saw a Ford Fiesta parked down near the pub. It had a radio telephone. I recognized the fittings and the antenna.'

'MacKenzie. Yes. None of the senior staff have the standard radiotelephone fittings nowadays. It's too conspicuous.'

'I climbed in here. I found the body. I phoned you. End of story.'

'I appreciate it, Werner.'

'Smart boy, your MacKenzie. How did he get on to her? She's not easy to follow, Bernard. What did she do that led your boy right here?'

'I don't know, Werner.'

'And he didn't phone in to tell you what he was doing?'

'What are you trying to say, Werner?'

'Your MacKenzie was one of them, wasn't he? It's the only explanation that fits. He was a KGB employee. He told you nothing. He helped them do whatever they had to do, then the black girl silenced him.'

'It's a tempting theory, Werner. But I don't buy it. Not yet anyway. I'd need more than that to believe that MacKenzie was a KGB employee.'

'So how did he track them down? Was it just luck?'

'You saw the body upstairs, Werner. It's not pretty, is it? You and I have seen plenty of that sort of thing, but you went a bit green and I needed a drink. I don't see it as a woman's deed. She fires a gun; splashes a lot of blood. There are screams and cries and a man mortally wounded. She sees his death agonies. She fires again; more spurting blood. Then again. Then again.' I rubbed my face. 'No. I don't think a woman would do it that way.'

'Then perhaps you don't know much about women,' said Werner feelingly.

'Crime passionel, you mean. But this is not the case of a woman who surprises her lover in bed with her rival. This was cold-blooded murder. MacKenzie was seated on a chair in the middle of the room. No evidence of any sexual motive. The bed was not even rumpled.'

'If not the black woman, who?'

'It wasn't done by a woman. It was a man; men probably, a KGB hit team.'

'Killing one of their own people,' said Werner, resolutely holding to his theory.

'If the KGB had recruited MacKenzie at Cambridge and then he was able to get a job in the department, they'd be keeping him in deep cover and waiting for him to get a desk for himself. They wouldn't kill him.'

'So, if he wasn't a KGB agent, whatever secret did your MacKenzie discover that made it necessary to kill him?'

'MacKenzie was no great detective, Werner. He was just a sharp young kid with a brilliant academic record from Cambridge. He wasn't even an ex-copper; no investigative experience, no training, and he wasn't a natural the way you are a natural. He'd never be able to trace an experienced KGB agent to a safe house. He was lured here, Werner. Someone was providing him with clues he had to fall over.'

'Why?'

'It was our safe house, Werner. A closely guarded departmental secret. The KGB bastards wanted to show us how clever they are.'

'And murder your probationer to rub salt in?' Werner was not convinced. He drank some more gin, looking at it after he sipped it as if he thought it might be poisoned. 'Strange-flavoured stuff this…' He read the label. '… oude jenever. It's not like real schnapps.'

'Hollands; it's supposed to taste like that,' I said. 'It was used as a medicine when they first concocted it.'

'You'd have to be damned ill to need it,' said Werner, pushing it aside. 'A deliberate murder?'

'He was seated in that chair in the middle of the room, Werner, His executioner was behind him. The pistol held against the top of the spine. It's the way the Okhrana executed Bolshevik revolutionaries in the time of the Tsar. In the nineteen-twenties the Tcheka hunted down white Russian émigré's in Paris and Berlin. Some of them were killed in that fashion. In the Spanish Civil War, Stalin's NKVD went to Catalonia and executed dozens of Trotskyites like that.'

'But why would a KGB hit team be so theatrical? And what did the black girl come here to do?'

'She came to see me. Or, more accurately, she saw me when she came to London.'

'What did she come to see you about?'

I hesitated about my reply. I poured myself another shot of gin and drank some. I'd always liked the curious malty flavour of Hollands gin and now I welcomed the fiery path it blazed to my stomach.

'You'll have to tell me,' said Werner. 'We're both too deep into this one to hold back any secrets.'