“Procurators are a bit like district attorneys. They decide whether to prosecute a case in court. Zeng asked me to provide him with detailed daily reports on the progress of the case. He seemed to know a lot about it already.” He looked at Margaret. “I mean, it was unusual, but he is a DPG. I never really thought anything about it.”

Margaret whistled softly. “Well, that tells us something anyway.”

“What?”

“Our man’s powerful enough to have the equivalent of a district attorney in his pocket.” She glanced apprehensively at Li. “That makes him pretty formidable opposition.”

“Thank you for those words of encouragement,” Li said dryly.

She smiled, and thought at least they could still smile. But the smile faded as she remembered that in the morning she would be boarding a plane and Li would be left to face this on his own. She didn’t want to leave him. She wished he could get on the plane with her and they could both leave all this behind. The game was no longer a game. It had turned dark and frightening.

Li turned right into Dongzhimennei and drew in at the kerb beside Mei Yuan’s jian bing house. Mei Yuan rose from her stool as soon as she saw who it was. She gave Margaret a wide smile and said to Li, “You are a little late for breakfast today.”

Li shook his head. “No, we are early for breakfast tomorrow.” Margaret checked the time. It was nearly 6 p.m. “Two jian bing,” Li said. “It has been a long day.”

“It has,” Mei Yuan said, beginning her preparations for the cooking. “I have been waiting for you for hours. I have a solution for your riddle.”

Li and Margaret exchanged glances. “The one about the three murders and the cigarette ends?” Margaret asked.

Mei Yuan nodded. “You said he deliberately left the cigarette ends beside each of the bodies because he knew that you would find them and match the DNA.”

“That’s right,” Li said. “Why?”

“I think it is so obvious,” Mei Yuan said, “that maybe I have not understood the question properly.”

Margaret was intrigued. “So why do you think he did it?”

Mei Yuan shrugged. “To make you believe these murders are connected—when there is no connection.”

Li frowned. “But why would he do that?”

“Wait a minute,” Margaret said. “You once told me that you conducted thousands of interviews to track down a man who murdered a whole family during a burglary. And it took you how long?”

“Two years.”

“So how long was it going to take you to track down all those migrant workers from Shanghai, and all the petty drug dealers and gay boys?”