‘Yes, that’s possible,’ I admitted. I rubbed a perfectly circular area of smooth skin on my otherwise stubbly face: it’s where a mosquito bit me when I was in Turkey, and ever since then I’ve never had to shave it. But quite often I find myself rubbing it when I feel uneasy about something. And if there’s one thing guaranteed to make me feel uneasy, it’s a client playing detective. I didn’t rule out what he was suggesting might have happened, but it was my turn to play the expert: ‘Possible, but messy,’ I said. ‘I can’t think of a better way of raising the alarm than making your own private Reichstag. Playing Van der Lubbe and torching the place doesn’t sound like the sort of thing a professional thief would do, but then neither does murder.’ There were a lot of holes in that of course: I had no idea that it was a professional; not only that, but in my experience it’s rare that a professional job also involves murder. I just wanted to hear my own voice for a change.

‘Who would have known she had jewels in the safe?’ I asked.

‘Me,’ said Six. ‘Grete wouldn’t have told anyone. I don’t know if Paul had.’

‘And did either of them have any enemies?’

‘I can’t answer for Paul,’ he said, ‘but I’m sure that Grete didn’t have an enemy in the world.’ While I could accept the possibility that Daddy’s little girl always brushed her teeth and said her prayers at night, I found it hard to ignore how vague Six was about his son-in-law. That made the second time he was uncertain about what Paul would have done.

‘What about you?’ I said. ‘A rich and powerful man like yourself must have your fair share of enemies.’ He nodded. ‘Is there anyone who might hate you bad enough to want to get back at you through your daughter?’

He re-kindled his Black Wisdom, puffed at it and then held it away from him between the tips of his fingers. ‘Enemies are the inevitable corollary of great wealth, Herr Gunther,’ he told me. ‘But these are business rivals I’m talking about, not gangsters. I don’t think any of them would be capable of something as cold-blooded as this.’ He stood up and went to attend to the fire. With a large brass poker he dealt vigorously with the log that was threatening to topple out of the grate. While Six was off-guard I jabbed him with one about the son-in-law.

‘Did you and your daughter’s husband get on?’

He twisted round to look at me, poker still in hand, and face slightly flushed. It was all the answer that I needed, but still he tried to throw some sand in my eyes. ‘Why ever do you ask such a question?’ he demanded.