Müller turned to Schmidt, who was sitting in the rear of the car, leafing through the pages of various files, as though he might find the answer in them. ‘What’s your feeling, Jonas, about those bus and train tickets – the only link to Lotti Rolf?’

Schmidt shrugged. ‘I think you know as well as I do, Comrade Hauptmann, that it’s a very tenuous link. It’s so odd that the purse still had money in it. Perhaps she wasn’t even the woman in the argument Frau Abt witnessed.’

‘Says she witnessed,’ interjected Tilsner. ‘However, I do think there’s something in the Lotti trail – even if it’s some sort of strange set up by the Stasi. Let’s face it, Karin. You were attacked in her apartment by assailants unknown – although Jonas has lifted Bahlow’s fingerprints from the flat. Bahlow himself, though, seemed unperturbed by that and had a perfectly logical explanation – if we buy it.’

Müller gave a long sigh. ‘The trouble is, we don’t know what’s true, and what isn’t. Although we do know others had an interest in Lotti’s whereabouts, because of our encounter with the fake Stasi agent at the cottage in Kirnitzschtal.’

The three of them sat in silence for a few moments.

‘So if we’re not barking up the wrong tree with Lotti,’ continued Müller, ‘we still need to find her. And perhaps when and if we do, we don’t take her in for questioning straight away but just watch her for a period, to see if she leads us anywhere interesting. And then, of course, there’s Arnold Southwick. Surely we should be able to establish if the body’s his or not?’

Tilsner lit a cigarette, provoking both Müller and Schmidt to wave the smoke back towards him. ‘To do that,’ he said, after taking a long draw of nicotine-infused fumes, ‘we might need the co-operation of the British police. That won’t be easy.’

‘Could you chase that up please, Werner?’ asked Müller. ‘And see if you can get hold of his dental records – if we can’t establish that he’s still alive.’

‘I’ll try. But it’s easier said than done. Especially as the Stasi have now come up with their own alternative narrative that doesn’t seem to involve either Southwick or Rolf. They won’t give up on that easily. Perhaps the direct approach is best. How are your relations with Jäger these days?’

Müller laughed. ‘Virtually non-existent. We’ve had no contact for ages until now.’

‘But he’s always held a torch for you,’ insisted Tilsner.

Müller found herself reddening under Tilsner’s gaze. ‘I don’t know how you work that one out. Most of the time he causes me nothing but problems. What are you suggesting, anyway?’

‘Well, you have that knowledge of what he got up to in the war . . .’