She paused for effect. “In my view these were execution-style killings, Detective, carried out by a very experienced professional.” Her words had a sobering effect on everyone in the room.

Li stood very still. You’re saying the killer was a professional? he had said to Old Yifu. Some Triad hit-man, his uncle had responded. These were no casual killings, Li Yan.

“Can I ask a question?” Margaret said.

“Go ahead.”

“What makes you think the burn victim from yesterday and the two we’ve looked at today are linked?”

“Why do you think I do?”

“Because you wouldn’t have asked me to perform these autopsies today if you hadn’t thought they were connected.”

Li nodded. There was logic in that. The students waited with bated breath. He said, “I don’t think these are matters we should be discussing in front of your students.” And there was a collective groan.

“Perhaps not,” Margaret conceded. She turned to the disappointed students, who were just beginning to get involved. “Leave your gowns and your masks with Professor Xie’s assistants, and I’ll see you in class in the morning.”

As the students filed out, Li and Margaret and Professor Xie moved away from the autopsy table. Li said, “There was a single cigarette end found at each crime scene. The same brand.”

“One I might know?”

“Marlboro.”

“Oh, yes,” she said. “Marlboro Country. Where the cowboys ride around with oxygen tanks on their backs to help them breathe.” She paused. “You know, there seem to be a hell of a lot of people who smoke in this country. Don’t you know it’s bad for you?”

“The American tobacco companies must have forgotten to tell us that,” Li said.

“Well, they would, wouldn’t they?” she said. “I mean, it’s a big market. If they flood China with cigarettes they’ll put big bucks in the pockets of the shareholders back home. You know, the ones who gave up smoking years ago because it was damaging their health.”

Professor Xie asked, “There was only a single cigarette end at each scene?” Li nodded.

Margaret snorted. “And you think that it might be the same killer, smoking the same brand of cigarette, who smoked one at each crime scene and left the butt there for us to find?” She clearly thought this stretched the bounds of credibility. “The same man who was so professionally meticulous in the execution of these crimes? You think he’d be careless enough to leave a cigarette end behind?” She shook her head. “It seems pretty unlikely to me.”

Li shrugged. “Perhaps so. But it does not change the fact that the cigarette ends were there.”

Margaret turned to Professor Xie. “Do you have facilities for DNA testing here?”

“Of course.”

She looked at Li. “Then, if there’s any trace saliva on the cigarette butts, you can match the DNA, and tell immediately if they were smoked by the same man.”