‘I think the Bürgermeister takes your point, Fabel,’ Van Heiden said, quietly and without anger.

‘If your answers do not satisfy me, Herr Doktor Schreiber,’ Fabel continued, ‘then I am going to arrest you here and now. And believe me, I will lead you through the Rathaus in handcuffs. So I think you should exhibit a little more candour than you have thus far.’ Fabel leaned back. ‘Did you murder Angelika Blüm?’

‘Christ … no.’

‘Then what were you doing at her apartment the night she was murdered?’

‘Angelika was an old friend. We saw each other now and again.’

Fabel’s face hardened. ‘I thought I made myself clear, Herr Schreiber. We can do this here or at the Präsidium. And unless you start being totally honest with us – and I mean about everything – then we’ll do it on our ground, not yours. Let’s start with the true nature of your relationship with Frau Blüm. How long had you been having an affair?’

Schreiber looked empty. He had been scrabbling around for some scrap to cover at least something of his privacy and Fabel had snatched it away from him.

‘A year. Maybe a little longer. As you probably know we had been intimate years ago. I had asked Angelika to marry me at the time but she turned me down. We remained friends throughout the years and then, somehow, something began to spark between us again.’

‘Is Frau Schreiber aware of this relationship?’ asked Van Heiden.

‘No. God, no. Karin has no idea. Neither of us wanted her to get hurt.’

‘So you didn’t plan to leave your wife?’ Fabel asked.

‘No. Or at least not now. I had suggested it to start with but Angelika didn’t want us to move in together. She wanted her independence and I suppose the arrangement … well, suited her. Anyway, like I said, we didn’t want Karin or the kids to get hurt.’

‘It doesn’t sound like a particularly deep relationship.’

Schreiber leaned forward onto the desk. He picked up a pen and fiddled with it, turning it end to end between his fingers. ‘That’s not true. We cared for each other. It’s just that we were being …’ he paused to find the right word – ‘practical. The other thing was that we always had a sense of unfinished business between us.’

Fabel decided to play another hunch. ‘Would I be right in saying that Frau Blüm wanted to end the relationship?’

Schreiber looked stung. ‘How did you …’

Fabel cut him off. ‘Was that why you were up there that evening? Were you trying to talk Frau Blüm out of ending the relationship?’

‘No. We had already agreed to stop seeing each other.’

‘I take it you had stayed the night on previous occasions?’

Schreiber nodded. ‘When circumstances allowed.’

‘In other words when you had a credible alibi to offer your wife.’

Schreiber made a small signal of resignation with his shoulders.

‘So I assume you had some stuff in Frau Blüm’s apartment and you were picking it up that night.’