Schreiber shook his head. ‘No, the publishing arm is their main business, but Eitel is involved in dozens of other areas. Information technology is one. Property development is another.’

Fabel nodded thoughtfully. ‘Was Eitel’s father there? Wolfgang Eitel?’

‘No. he wasn’t. That’s where I draw the line … I won’t share a platform with a Nazi like him, no matter how beneficial the cause. I think that’s why he was kept away … despite their public shows of solidarity, Norbert Eitel is very much aware of the liability his father represents to his political ambitions.’

‘You must have been shocked by Kastner’s murder.’

‘That’s an understatement. It was a terrible shock. You remember Innensenator Hugo Ganz?’

Fabel nodded. He thought of Ganz’s scrubbed, fleshy pink face.

‘Frau Kastner worked quite closely with Herr Ganz. Specifically to do with environmental and property-development projects. She provided the legal back-up. Innensenator Ganz was very upset by Frau Kastner’s death. That’s why I think he was so … emphatic when you met him last.’

‘Presumably you remember where you were when Frau Kastner went missing?’

‘I was attending an environmental conference in Rome.’ Schreiber spoke without emotion. Then a small hope lit up his face. ‘That’s right! I wasn’t even in the country when she was killed. And I have a hundred witnesses. And when was the second victim killed?’

‘The early hours of Wednesday the fourth,’ said Fabel.

Schreiber scrabbled though his desk diary. ‘I was at home with my family. They can verify it.’

Fabel didn’t look impressed. ‘All I am interested in just now is Frau Blüm’s murder. And you were there immediately before she was killed.’

‘But I had nothing to do with it. Nothing at all.’ A hint of defiance was beginning to creep into Schreiber’s tone. The realisation that he had alibis for the other two killings clearly emboldened him.

Fabel changed tack. ‘Did you know that Frau Blüm had been trying to get in touch with me, personally?’

‘No … no, I didn’t. What on earth for?’

‘I don’t know. I didn’t get a chance to return her calls,’ Fabel lied. It sounded better than saying he hadn’t bothered.

‘Do you think she thought she was in any kind of danger? Do you think that’s why she was trying to contact you?’ Schreiber didn’t wait for an answer. ‘Why didn’t she tell me? If she was afraid … why didn’t she talk to me?’

Fabel stood up. Van Heiden followed his lead. ‘I have no reason to believe that she felt in danger. All I know is she tried to get in touch with me three or four times before she died. But she didn’t indicate in any of the messages she left that she was in danger.’

Fabel made for the door without shaking Schreiber’s hand. ‘Like I say, Herr Doktor Schreiber, I may have more questions for you. And I’ll arrange for our forensics guy to come and take your fingerprints.’

Fabel had opened the heavy oak door when he turned back to face Schreiber. ‘One more thing. When was the last time you met or had any contact with Marlies Menzel?’