‘The only photograph is the one on his prison record,’ said Sohst, handing me a picture. I looked at it carefully. ‘It’s three years old, and his head will have been shaved of course, so it doesn’t help you much. Not only that, but he’s likely to be a great deal thinner. A KZ does tend to change a man. There is, however, one thing that should help you to identify him: he has a noticeable ganglion on his right wrist, which he could hardly obliterate.’

I handed back the photograph. ‘It’s not much to go on,’ I said. ‘Suppose I refuse?’

‘You won’t,’ said Heydrich brightly. ‘You see, either way you’re going to Dachau. The difference is that working for me, you’ll be sure to get out again. Not to mention getting your money back.’

‘I don’t seem to have much choice.’

Heydrich grinned. ‘That’s precisely the point,’ he said. ‘You don’t. If you had a choice, you’d refuse. Anyone would. Which is why I can’t send one of my own men. That and the need for secrecy. No, Herr Gunther, as an ex-policeman, I’m afraid you fit the bill perfectly. You have everything to gain, or to lose. It’s really up to you.’

‘I’ve taken better cases,’ I said.

‘You must forget who you are now,’ said Sohst quickly. ‘We have arranged for you to have a new identity. You are now Willy Krause, and you are a black-marketeer. Here are your new papers.’ He handed me a new identity card. They’d used my old police photograph.

‘There is one more thing,’ said Heydrich. ‘I regret that verisimilitude requires a certain amount of further attention to your appearance, consistent with your having been arrested and interrogated. It’s rare for a man to arrive at Columbia Haus without the odd bruise. My men downstairs will take care of you in that respect. For your own protection, of course.’

‘Very thoughtful of you,’ I said.

‘You’ll be held at Columbia for a week, and then transferred to Dachau.’ Heydrich stood up. ‘May I wish you good luck.’ I took hold of my trouser band and got to my feet.

‘Remember, this is a Gestapo operation. You must not discuss it with anyone.’ Heydrich turned and pressed a button to summon the guards.

‘Just tell me this,’ I said. ‘What’s happened to Six and Helfferich, and the rest of them?’