When she’d contacted him, Bahlow had sounded distracted – frightened almost. She’d asked if they could meet, but he wouldn’t give her an answer over the open line. The invitation to meet here – high above the city of Dresden, on the viewing platform of the historic Schwebebahn suspension railway – only came some thirty or so minutes later, in a sealed envelope brought to her office by a motorcycle courier.

‘Things are becoming more complicated, Comrade Hauptmann,’ he said, by way of introduction. ‘I’m not sure it’s a good idea for us to have further contact. In any case, you have your suspects under arrest now, I believe?’

The question was, of course, redundant. The Stasi would know about every move they’d made. It was Bahlow himself, after all, who’d led them to Rolf and Southwick’s squat, in his ridiculous sunglasses disguise, even if he wasn’t admitting it.

‘We do have two people under arrest, although one of them is being treated in hospital. However, I’m not sure I buy their story – or at least, her story – which is why I wanted to talk to you.’

The Stasi officer grunted. He didn’t turn to face her. Instead, he seemed to be intent on solemnly gazing at the Dresden cityscape below, bathed in the wan morning light.

Without eye contact, Müller focused on the back of Bahlow’s head. ‘Lotti Rolf claims that Concrete Man was – in all probability – a Stasi officer. She claims he died accidentally in a fight with Southwick . . .’ Bahlow snorted in disbelief. Müller ignored him and continued. ‘And that, contrary to what the pathologist says, he hit the back of his skull in a fall rather than being struck. And that both of them tried to save him from his concrete grave, without success.’

This time Bahlow gave a small laugh, and started shaking his head. He turned to hold Müller’s gaze. ‘She’s a one, that Lotti Rolf. I’ll give her that. A game girl. But a seasoned liar. Let me ask you something, Comrade Hauptmann; in all your dealings with pathologists in the Republic, have you ever known any of them to deliberately lie? Or – to put it another way – did Dr Giesler seem like the sort who would change his findings, no matter what pressure he was put under?’

‘No,’ admitted Müller.

‘No, precisely. There is only one liar here, and that is Lotti Rolf. For my own part, I’ll admit I haven’t been open with you about everything, but for my own reasons I’ve tried to point you in the right direction. In fact, I’ve put my own job in jeopardy in doing precisely that.’