Hoffman needed no persuasion. One of the men was called Bruno, he told Kriminaldirektor Frank; he was a fairly regular diner at Das Bayerischer Haus. In fact, he’d held a dinner there for his fortieth birthday and used the private dining room, which was how he was aware of it. Hoffmann remembered showing him the room and pointing out the door concealed in the panelling and the staircase down to the yard. In August, Bruno had come to him with a favour to ask: could he use that room for a meeting, and would Herr Hoffmann mind leaving the door from the yard and the one in the panelling unlocked? He’d thought no more of it. Bruno was most generous, and when he’d asked him again in early December for the same favour, he was happy to oblige. He’d had absolutely no idea he was doing anything wrong and he—

‘Do you know his surname?’

‘Whose surname?’

‘You’ve been doing so well, Hoffmann, please don’t spoil it now. Bruno’s surname!’

‘Bergmann, sir: Bruno Bergmann. And if it’s of any help, I even know where he works.’

‘You have done very well, Kriminaldirektor Frank: your work is as thorough as I have come to expect. You will certainly receive a commendation for this.’

‘But it’s not complete, sir. I need to arrest this Bruno Bergmann.’

Gruppenführer von Helldorf avoided looking at him and shifted uncomfortably behind his large desk, moving a bottle of ink from one side of it to the other and carefully straightening his blotting pad. ‘I’m afraid your role in this investigation has come to an end, Gunther. My instructions are that the Gestapo will handle matters from now on. I am told that as they began this investigation, they should be allowed to complete it.’

Manfred Lange wasted no time. Within minutes of Gruppenführer von Helldorf passing on Bruno Bergmann’s name, he headed for Spandau Locomotive Engineering along with a dozen of his men: he didn’t want to leave anything to chance. He sent another team to Bergmann’s house to search it and arrest his wife.

Within an hour – Lange was proud he’d been so quick – they were back at 8 Prinz Albrecht Strasse. Normal practice was to beat the suspect up and then leave him in a dark cell for a couple of hours: received wisdom was that after that they were much easier to interrogate.

But Lange was impatient. He didn’t want that patronising bastard from the Kripo getting any credit whatsoever. He ordered his men to take Bergmann down to the lower basement. ‘You know where I mean, and you know what to do.’