The Ganz family, what remained of it following a second anonymous call to the Alex informing us where the body of Liza Ganz was to be found, lived south of Wittenau in a small apartment on Birkenstrasse, just behind the Robert Koch Hospital where Frau Ganz was employed as a nurse. Herr Ganz worked as a clerk at the Moabit District Court, which was also nearby.

According to Becker they were a hard-working couple in their late thirties, both of them putting in long hours, so that Liza Ganz had often been left by herself. But never had she been left as I had just seen her, naked on a slab at the Alex, with a man stitching up those parts of her he had seen fit to cut open in an effort to determine everything about her, from her virginity to the contents of her stomach. Yet it had been the contents of her mouth, easier of access, which had confirmed what I had begun to suspect.

‘What made you think of it, Bernie?’ Illmann had asked.

‘Not everyone rolls up as good as you, Professor. Sometimes a little flake will stay on your tongue, or under your lip. When the Jewish girl who said she saw our man said he was smoking something sweet-smelling, like bay-leaves or oregano, she had to be talking about hashish. That’s probably how he gets them away quietly. Treats them all grown-up by offering them a cigarette. Only it’s not the kind they’re expecting.’

Illmann shook his head in apparent wonder.

‘And to think that I missed it. I must be getting old.’

Becker slammed the car door and joined me on the pavement. The apartment was above a pharmacy. I had a feeling I was going to need it.

We walked up the stairs and knocked on the door. The man who opened it was dark and bad-tempered looking. Recognizing Becker he uttered a sigh and called to his wife. Then he glanced back inside and I saw him nod grimly.

‘You’d better come in,’ he said.

I was watching him closely. His face remained flushed, and as I squeezed past him I could see small beads of perspiration on his forehead. Further into the place I caught a warm, soapy smell, and I guessed that he’d only recently finished taking a bath.

Closing the door, Herr Ganz overtook and led us into the small sitting-room where his wife was standing quietly. She was tall and pale, as if she spent too much time indoors, and clearly she had not long stopped crying. The handkerchief was still wet in her hand. Herr Ganz, shorter than his wife, put his arm around her broad shoulders.

‘This is Kommissar Gunther, from the Alex,’ said Becker.