Harry shifted uncomfortably in his chair.

‘Yes, Harry, it is correct that I knew Lisbeth was having an affair with this man, but I didn’t find out until this summer.’

It began to drizzle again. Raindrops spattered against the window.

‘Did she tell you that?’

Wilhelm shook his head. ‘She would never have done that. She came from a family where things were not talked about. It would never have come out if we hadn’t been doing up the flat. I found a letter.’

‘Yes?’

‘The external wall in her study is just bare brick. It’s the original wall from when the building work was done at the turn of the century. Solid, but it gets absolutely freezing in winter. I wanted to clad it with panelling and insulate it on the inside. Lisbeth objected. I thought that was weird, because she was a practical girl, brought up on a farm, not the type to become sentimental about an old brick wall. So one day, when she was out, I examined the wall. I didn’t find anything until I shoved her desk to one side. I still couldn’t see anything out of the ordinary, but I poked at each of the bricks. One moved just a little. I pulled, and it came away. She had camouflaged the cracks round it with grey building mortar. Inside I found two letters. The name of Lisbeth Harang was on the envelope and a poste restante address I had no idea she had. My first reaction was to put the letters back unread and convince myself that I had never seen them. But I’m a weak man. I wasn’t capable of it. “ Liebling, you are always in my thoughts. I can still feel your lips against mine, your skin against mine” – that’s how the letter begins.’

The bed made a rippling noise.

‘The words smarted like lashes from a whip, but I kept on reading. It was eerie because every word that was written could have been written by me. When he finished saying how much he loved her, he went on to describe what they had done together in the hotel room in Prague in some detail. It wasn’t the description of their love-making that hurt me most, though. It was when he quoted what she had obviously said about our relationship. That for her it was just “a practical solution to a loveless life”. Can you imagine how something like that feels, Harry? When it turns out that the woman you love has not only deceived you, but she has never loved you. Not to be loved – isn’t that the essential definition of a failed life?’

‘No,’ Harry said.

‘No?’

‘Carry on, if you wouldn’t mind.’

Wilhelm gave Harry a searching look.

‘He’d enclosed a photo of himself. I presume she had begged him to send it. I recognised him. He was the Norwegian we met at a cafe in Perlova, a rather shady area of Prague with prostitutes and what were, to all intents and purposes, brothels. He was sitting in the bar when we came in. I noticed him because he was just like one of those mature, distinguished gentlemen that Boss uses as models. Elegantly dressed and old, actually. But with such young, playful eyes that men need to keep an extra careful eye on their wives. So I was not particularly surprised when the man came over to our table after a little while, introduced himself in Norwegian and asked us if we would like to buy a necklace. I thanked him politely and said no, but when he took it out of his pocket anyway and showed it to Lisbeth, she was swooning of course and said that she loved it. The pendant was a red diamond in the shape of a five-pointed star. I asked him what he wanted for the star and when he gave me a price that was so ridiculously over the top that it could only be interpreted as provocation, I asked him to leave us. He smiled at me as if he’d just won a victory, wrote down the address of another cafe on a slip of paper and said that we could find him there at the same time the following day if we changed our minds. Naturally he gave the piece of paper to Lisbeth. I can remember that I was in a bad mood for the rest of the morning. But then I forgot everything. Lisbeth is clever at making you forget. On occasion she manages…’ Wilhelm ran his finger under his eye, ‘… to do that with her mere presence.’

‘Mm. What was in the other letter?’

‘It was a letter she had written and obviously tried to send to him. The envelope was stamped with “Return to sender”. She wrote that she’d tried to get in touch with him in all sorts of ways, but no-one answered at the telephone number he’d given her and neither directory enquiries nor the Post Office had been able to trace him. She wrote that she hoped the letter would find him somehow and asked if he’d had to flee from Prague. Perhaps he was still beset by the same economic problems he’d had when he’d borrowed money from her?’

Wilhelm gave a hollow laugh.

‘If so, he should contact her, she wrote. And she would help him again. Because she loved him. She couldn’t think of anything else – the separation was driving her mad. She’d hoped it would pass with time, but instead it had spread like a disease and every centimetre of her body ached. And some centimetres obviously ached more than others because she wrote to him that when she let her husband – me, in other words – make love to her she closed her eyes and pretended it was him. I was shocked, of course. Yes, stunned. But I died when I saw the date stamp on the envelope.’

Wilhelm squeezed his eyes shut hard again.

‘The letter was sent in February. This year.’

A new flash of lightning cast shadows on the wall. The shadows remained there like spectres of light.

‘What do you do?’ Wilhelm asked.

‘Yes, what did you do?’

Wilhelm smiled weakly.

‘My solution was to serve foie gras with white wine. I covered the bed with roses and we made love all night. As she slept through in the early morning I lay watching her. I knew that I could not live without her, but I also knew that to make her mine, first of all I would have to lose her.’

‘And so you planned the whole thing. Stage-managed how you were going to take the life of your wife and at the same time ensure that the man she loved would be blamed.’

Wilhelm shrugged his shoulders.

‘I went to work in the same way that I did with any stage production. Like all men of the theatre, I know that the most important thing is the illusion. The deceit must be presented as so credible that the truth would seem extremely unlikely. That may sound as if it is tricky to achieve, but in my profession you quickly discover that it is generally easier than the alternative. People are much more used to hearing lies than the truth.’

‘Mm. Tell me how you did it.’

‘Why should I risk that?’

‘I can’t use any of what you say in a court of law anyway. I have no witnesses and I entered your flat illegally.’

‘No, but you’re a smart fellow, Harry. I might give something away that you can use in the investigation.’

‘Maybe, but I think you’re willing to take that risk.’

‘Why?’

‘Because you really want to tell me. You’re burning to tell me. To hear yourself say it.’

Wilhelm Barli laughed out loud.

‘So you think you know me, do you, Harry?’

Harry shook his head as he searched for his packet of cigarettes. In vain. He may have lost them when he fell from the roof.

‘I don’t know you, Wilhelm. Or any others like you. I’ve worked with killers for fifteen years and I still know only one thing: that they’re searching for someone to reveal their secrets to. Do you remember what you made me promise in the theatre? To find the killer. Well, I’ve kept my promise. So let’s make a deal. You tell me how you did it and I’ll tell you the proof we’ve got.’

Wilhelm studied Harry’s face. One hand stroked the mattress.

‘You’re right, Harry. I want to tell you. Or to be more precise, I want you to understand. From what I know of you, I think you can take it. You see, I’ve been following your progress ever since this case started.’

Wilhelm laughed when he saw Harry’s face.