‘Beautiful,’ said Fabel sincerely. He handed the volume back. ‘I’m sorry to disturb you at home, Herr Yilmaz, and thank you for seeing me at such short notice. I just felt that it was a little less formal … I would like to ask you some questions about a case I’m working on.’

‘Yes, you said on the phone. Are you sure this shouldn’t be done more formally? Specifically, with my lawyer present?’

‘That, of course, is up to you, Herr Yilmaz. But I want to make it clear that I am speaking to you not as a suspect but simply as someone who can perhaps provide some helpful information. By the way, Herr Yilmaz, before we go any further, my condolences on the death of your cousin.’

Yilmaz moved over towards a coffee table and two leather armchairs by the wall. ‘Please, Herr Fabel, sit down.’ The blonde housekeeper came in with a cafetière. She poured two cups and left.

‘Thank you, Herr Fabel. It’s not often that a Hamburg policeman addresses me so … politely. It is sad, but Ersin was always so … impetuous, shall we say. Anyway, ask your questions and I’ll do what I can to help. What is this case? You said on the phone you wanted to talk to me about Hans Klugmann? I’ve already spoken to your colleagues Herr Buchholz and Herr Kolski about him. I’ve told them, I have no idea where he is.’

Fabel understood Kolski’s annoyance about this visit to Yilmaz: what were LKA7 doing looking for Klugmann?

‘Yes. But that’s not the case I’m investigating. I’m looking into the murder of a young prostitute who rented an apartment from Klugmann. We know her only as “Monique”.’

Yilmaz sipped his coffee without taking his eyes off Fabel. There was no reaction to the name. Not a flicker in the eye. Nothing.

‘Was Monique working for you?’ Fabel asked. ‘Even indirectly, through Klugmann?’

‘No, Herr Fabel, she was not.’

‘Listen, Herr Yilmaz, I have no interest in your business or other activities. All I am trying to do is to catch a serial killer before he strikes again. What you tell me here is off the record.’

‘I appreciate that, Herr Fabel, and I reiterate: this girl was not working for me directly or indirectly. Whatever I may be involved in, I do not run cheap back-street prostitutes …’

‘Could Klugmann have been running her as a private venture?’

‘Possibly. I really wouldn’t know. Klugmann is not one of my people, even if your colleagues from LKA7 Organised Crime insist that he is.’

‘You have to admit that someone with his … employment history would be very useful to your organisation.’

‘Herr Hauptkommissar, we have been frank with each other thus far. In the same spirit of candour I’ll tell you this much – and as you say, off the record. Klugmann is someone on the fringes. You’re right, his particular background makes him very useful, but he has never been fully trusted by anyone on our side of the fence. There’s always a lingering doubt about ex-policemen.’ Yilmaz took a sip from his coffee cup. ‘My cousin Ersin used Klugmann as a freelance resource, but that’s as far as it went.’