She blew smoke out of both nostrils like an angry bull. ‘Not especially,’ she said. ‘At least, not until you mentioned it.’ She thumped the dashboard and swore. ‘But what if he had asked which school Emmeline goes to? What would you have done if he’d turned up there and found out that my real husband is dead? I’d like to know that.’

‘He wouldn’t have.’

‘You seem very sure of that. How do you know?’

‘Because I know how private detectives operate. They don’t like to walk right in after the police and ask all the same questions. Usually they like to come at a thing from the other side. Walk round it a bit before they see an opening.’

‘So you think that this Rolf Vogelmann is suspicious?’

‘Yes, I do. Enough to warrant detailing a man to keep an eye on his premises.’

She swore again, rather more loudly this time.

‘That’s the second time,’ I said. ‘What’s the matter with you?’

‘Why should anything be the matter? No indeed. Single ladies never mind people giving out their addresses and telephone numbers to those whom the police believe to be suspicious. That’s what makes living on one’s own so exciting. My daughter is missing, probably murdered, and now I have to worry that that horrible man might drop round one evening for a little chat about her.’ She was so angry she almost sucked the tobacco out of the cigarette paper. But even so, this time when we arrived at her apartment in Lepsius Strasse, she invited me inside.

I sat down on the sofa and listened to the sound of her urinating in the bathroom. It seemed strangely out of character for her not to be at all self-conscious about such a thing. Perhaps she didn’t care if I heard or not. I’m not sure that she even bothered to close the bathroom door.

When she came back into the room she asked me peremptorily for another cigarette. Leaning forwards I waved one at her which she snatched from my fingers. She lit herself with the table lighter, and puffed like a trooper in the trenches. I watched her with interest as she paced up and down in front of me, the very image of parental anxiety. I selected a cigarette myself, and tugged a book of matches from my waistcoat pocket. Hildegard glanced fiercely at me as I bent my head towards the flame.

‘I thought detectives were supposed to be able to light matches with their thumbnails.’

‘Only the careless kind, who don’t pay five marks for a manicure,’ I said yawning.

I guessed that she was working up to something, but had no more idea of what it could be than I had of Hitler’s taste in soft-furnishings. I took another good look at her.