Von Greis’s apartment was on the third floor of a smart apartment-block. There was no sign of a concierge, so I went straight on up. I hit the door-knocker and waited. After a minute or so had elapsed I bent down to look through the letter-box. To my surprise I found the door swinging open as I pushed back the flap on its tight spring.

I didn’t need my deerstalker-hat to realize that the place had been turned over, from top to bottom. The long hallway’s parquet floor was covered with books, papers, envelopes and empty wallet files, as well as a considerable amount of broken glass which was referable to the empty doors of a large secretaire bookcase.

I walked past a couple of doors and stopped dead as I heard a chair scrape in the grate of one of the rooms ahead of me. Instinctively I reached for my gun. The pity was, it was still in my car. I was going for a heavy cavalry sabre mounted on the wall when behind me I heard a piece of glass crack underneath someone’s foot, and a stinging blow to the back of my neck sent me plunging through a hole in the earth.

For what seemed like hours, although it must only have been a few minutes, I lay at the bottom of a deep well. Fumbling my way back to consciousness I became aware of something in my pockets, and then a voice from a long way off. Then I felt someone lift me under the shoulders, drag me for a couple of miles and shove my face under a waterfall.

I shook my head and squinted up to look at the man who had hit me. He was almost a giant, with a lot of mouth and cheeks, like he’d stuffed each of them with a couple of slices of bread. There was a shirt round his neck, but it was the kind that belonged properly in a barber’s chair, and the kind of neck that ought to have been harnessed to a plough. The arms of his jacket had been stuffed with several kilos of potatoes, and they ended prematurely, revealing wrists and fists that were the size and colour of two boiled lobsters. Breathing deeply, I shook my head painfully. I sat up slowly, holding my neck with both hands.

‘Christ, what did you hit me with? A length of railway track?’

‘Sorry about that,’ said my attacker, ‘but when I saw you going for that sabre I decided to slow you down a bit.’

‘I guess I’m lucky you didn’t decide to knock me out, otherwise . . .’ I nodded at my papers which the giant was holding in his great paws. ‘Looks like you know who I am. Mind telling me who you are? It seems like I ought to know you.’