‘It’s okay, Jan,’ Mahmoot called from the far end of the office. ‘They’re cops … kind of. I wouldn’t have got you to come here if I thought there was a real danger.’

The Slav indicated a second chair, next to Mahmoot. ‘Please, Herr Fabel. Sit down.’ When Fabel complied he turned to the girl and spoke in German. ‘Martina, please give the Hauptkommissar his weapon back.’

The girl expertly slipped the magazine out from the grip of Fabel’s gun and handed them to him separately. Fabel holstered the Walther and put the magazine into his pocket. As he did so, he noticed that the girl carried the same model of automatic as Hansi Kraus had picked up in the disused Schwimmhalle. The only difference was that this gun was not decorated with the presentational inlays and tooling.

He turned to Mahmoot. ‘You okay?’

Mahmoot nodded. ‘I’m sorry about this, Jan. But I think you ought to hear what they have to say. They reckon they’re after the same guy you are. They’ve been watching you for some time now – and they tailed me after our meeting on the ferry.’

Fabel turned to the Slav, whose smile did not engage his cold green eyes. ‘You’re some kind of Russian law enforcement? If so, why didn’t you go through the proper channels? I have to tell you that you’ve broken several German federal laws … the city is currently crawling with police hunting you after your attack on me …’

Mahmoot turned quickly in his chair and made a move to get up. The blonde girl waved the barrel of her automatic, indicating for him to remain seated.

‘You were attacked?’

Fabel nodded. ‘Your new friends are not as cuddly as they seem.’

‘I’m sorry about that, too, Herr Fabel,’ said the Slav. ‘But I could not afford the … complication of being taken into custody at that point. I’m sure you appreciate that I could have done you real, lasting harm had I chosen.’

Fabel ignored the statement. ‘Who are you? Who do you work for?’

The Slav’s smile again failed to ignite in the cold green eyes. ‘My name, at this stage, is unimportant. My colleague –’ he nodded in the direction of the golden-haired girl – ‘and I are officers of the Ukrainian counter-terrorist police. The Berkut.’

‘Ukrainian secret service?’

‘No … that would be the SBU – the Sluzhba Bespeky Ukrayiny – who, unfortunately, probably have their part to play in this drama.’

‘And what have these murders to do with terrorism?’

‘Directly? Nothing. Herr Fabel, I will explain everything in due course. I’m afraid there is a great deal to explain and my German has its limits, so I ask you to be patient. The main thing is I believe we would both benefit from an exchange of information.’

Fabel gave the Slav a hard stare. His German seemed pretty solid to him, despite the heavy accent. ‘What were you doing in Angelika Blüm’s apartment? And what were you doing outside the murder scene in St Pauli?’