I heard the bell in the hall and went to the window. Pulling it up I leant out to see who was working the bell-pull. Even three storeys up I could recognize Vogelmann’s head of distinctive red hair.

‘That’s a very common thing to do,’ said Hildegard. ‘Lean out of a window like a fishwife.’

‘As it happens, I might just have caught a fish. It’s Vogelmann. And he’s brought a friend.’

‘Well, you had better go and let them in, hadn’t you?’

I walked out on to the landing and operated the lever that pulled the chain to open the street door, and watched the two men climb up the stairs. Neither one of them said anything.

Vogelmann came into Hildegard’s apartment wearing his best undertaker’s face, which was a blessing since the grim set to his halitosic mouth meant that, for a while at least, it stayed mercifully shut. The man with him was shorter than Vogelmann by a head, and in his mid-thirties, with fair hair, blue eyes and an intense, even academic air about him. Vogelmann waited until we were all seated before introducing the other man as Dr Otto Rahn, and promised to say more about him presently. Then he sighed loudly and shook his head.

‘I’m afraid that I have had no luck in the search for your daughter Emmeline,’ he said. ‘I’ve asked everyone I could possibly have asked, and looked everywhere I could possibly have looked. With no result. It has been most disappointing.’ He paused, and added: ‘Of course, I realize that my own disappointment must count as nothing besides your own. However, I thought I might at least find some trace of her.

‘If there was anything, anything at all, that gave some clue as to what might have become of her, then I would feel justified in recommending to you that I continue with my inquiries. But there’s nothing that gives me any confidence that I wouldn’t be wasting your time and money.’

I nodded with slow resignation. ‘Thank you for being so honest, Herr Vogelmann.’

‘At least you can say we tried, Herr Steininger,’ Vogelmann said. ‘I’m not exaggerating when I say that I have exhausted all the usual methods of inquiry.’ He stopped to clear his throat and, excusing himself, dabbed at his mouth with a handkerchief.

‘I hesitate to suggest this to you, Herr and Frau Steininger, and please don’t think me facetious, but when the usual has proved itself to be unhelpful, there can surely be no harm in resorting to the unusual.’

‘I rather thought that was why we consulted you in the first place,’ Hildegard said stiffly. ‘The usual, as you put it, was something that we expected from the police.’

Vogelmann smiled awkwardly. ‘I’ve expressed it badly,’ he said. ‘I should perhaps have been talking in terms of the ordinary and the extraordinary.’