Wu cocked his head doubtfully. “Well, he was stabbed in the heart, up through the lower ribcage. But there were no signs of a struggle, no bruising or cuts on his hands or face. The pathologist thinks he may have been attacked from behind. Autopsy should confirm. Looks like it might have been some kind of gangland killing. He was lying face down in his own blood on a stretch of waste ground near Kunminghunan Road. A factory worker found him on his way to work this morning. The ground out there’s hard as concrete. No footprints in soil, or blood. In fact nothing for us to really go on at all. Forensics are doing fingernail and fibre tests, but I get a feeling about this, Li Yan. I don’t think they’re going to find anything. In fact, the only thing we picked up at all at the scene was a cigarette end, which is probably entirely unrelated.”

Li was suddenly interested, instincts aroused. “Just one? I mean, there weren’t any others lying around near by?”

“Not that we found.”

“What brand was it?”

“American. Marlboro, I think. Why?”

Detective Zhao said, “That’s odd. We found a Marlboro cigarette end close to the body out at Di’anmen.”

Qian leaned into the table. “It was a Marlboro brand cigarette end we found out at Ritan, wasn’t it, boss?”

Li nodded slowly, his interest fully ignited now. It was a remarkable coincidence, if, indeed, that was what it was. But he knew better than to go jumping to premature conclusions. There was a speculative buzz around the table. He asked Zhao to give them a rundown on the body found at Di’anmen.

Zhao was the baby of the section, a good-looking young man of around twenty-five. What he lacked in flair he made up for in sheer hard work and attention to detail. He was always self-conscious at these meetings, finding it difficult to give coherent expression to his thoughts in the group situation. He was much better dealing with people one to one. Colour flushed high on his cheekbones as he spoke. “He was carrying an ID card, so we know he was a building worker from Shanghai. Probably an itinerant. He may well have just arrived in Beijing looking for work, but there’s no known address for him here, no known associates. I’ve already faxed Public Security in Shanghai asking for his details.”

“How was he killed?”

“A broken neck.”

“He couldn’t just have fallen? An accident of some kind?”

“No. There’s absolutely no sign of trauma. He was found in a condemned siheyuan in a hutong that was cleared about a month ago. But the crime scene is so clean I think he was killed somewhere else and dumped there.”

“So what makes you think the cigarette end is connected to it?”