‘No,’ he said. ‘I knew no one called Heck. Now, please, Mo, let me go. You’re hurting me.’

Heck ignored the plea. ‘You’ve come out of it well, Albert. You must have put on quite a bit of weight. How long were you there?’

‘Two years, as I have already told you. I was very thin and sick at liberation. I think I came close to death. You cannot imagine the horrors of the place.’

‘Were you whipped?’

He hesitated, then shook his head.

‘What were you doing there at Auschwitz? I believe they made you work hard for your gruel if you were considered strong enough not to be gassed. What was your work? Tell me about your days. I will write the history of these years and I need to hear your testimony. Don’t be shy with me. Tell me everything.’

‘I’ve had enough of this, Mo. You said you were my friend, but you are hurting me.’

‘No, no, tell me about your work at the camp. Your labour day by day. Were you Sonderkommando, or shipped out to one of the factories?’

‘I . . . I worked in a mine.’

‘Mining what, may I ask?’

‘Coal. I shovelled coal into carts at the Janina mine at Libiaz, two hours walk to the north-east of Auschwitz. It was so cold in the winter and my shoes were falling apart.’

‘Now recite Kaddish for me.’

Rothstein looked uncomfortable. ‘What is that? I do not know what that is.’

‘Why, Kaddish is the Jewish prayer for the dying. Every Jew can say it. How can you not know what it is?’

‘But I told you, I was not brought up a Jew. I am Lutheran but of Jewish stock.’

‘Of course, I forgot. How foolish of me.’

‘I have had enough of this, Mo. You are treating me abominably. Please, let go of my arm.’

‘Take off your jacket and shirt, Albert. I want to see what those damned Nazis did to you. What scars they left on your poor young body.’

‘I don’t know what you mean?’

‘The Nazis, they hit everyone, they whip you and beat you with rifle butts. You must have suffered many injuries. Everyone did. Let me see the scars.’

‘No, I wasn’t whipped.’

‘I want you to strip to your waist, that’s all. I want to see your whole upper body. Will you do that for me? This is important. I am going to write a work of great scholarship. I need the evidence.’

Rothstein managed at last to pull his arm away from Heck’s grip and began scrabbling to his feet. ‘No, you are crazy. Why would you ask such a thing?’

Heck, too, was on his feet now. He flipped open his bag and pulled out a pistol. He thrust it up close to Rothstein’s face. ‘Just do it, Albert. If you are who you say, you have nothing to hide from me.’

‘I won’t do it.’ He was holding his arms tight around his body, as though he was naked already and trying desperately to cover his modesty or protect himself from humiliation.