She approached the hotel from the north, passing the Friendship Palace and its shady gardens where birds sang in cages, and wheeled her bicycle into the carpark, hot and uncomfortable in the scorching afternoon. A car horn sounded, but she paid it no attention. Motorists used their horns incessantly. It sounded again. Two short, insistent blasts and a longer one. She turned as a dark blue Beijing Jeep pulled in behind her and drew alongside. Her stomach flipped over as she recognised Li behind the wheel. The driver’s window wound down and he switched off the engine. He looked at her apprehensively. His battered face didn’t seem as bruised as it had earlier. “I tried to get you at the university,” he said. “They told me you’d quit.”

She nodded confirmation. “My flight’s at nine thirty tomorrow morning.”

He thought she seemed cold and distant. He wanted to ask why she had quit, why she was leaving, but he didn’t have the courage. “I just wanted to check with you,” he said. “About the AIDS test.”

Her disappointment manifested itself as anger. “Actually, I’m not interested. I’m no longer involved in your investigation, and I couldn’t care less if Chao tested positive or not.”

Li responded in kind, hurt by her tone. “And I couldn’t tell you, even if I wanted to . . . since you never requested the test.”

“What?” She glared at him, full of indignation.

“According to Professor Xie.”

“Well, that’s ridiculous. I spoke to him last night, on the way back here to change.”

“And asked him to test a sample of Chao’s blood for AIDS?”

“Of course.”

“He says you didn’t.”

“Then he’s a damn liar!”

“You want to tell him that?”

“Try stopping me.” She kicked down her bike stand, slipped the lock through the back wheel and rounded the Jeep to the passenger side. As she slipped into the seat she slammed the door shut and glared at Li. “And you believe him, do you?”

“No,” he said simply.

She stared at him for some moments. “What’s going on, Li Yan?”

“Someone doesn’t want us testing Chao Heng for AIDS.”

“Professor Xie?” Margaret was incredulous.

“Only on instruction from someone else.”

“Who?”

“I’ve no idea.”

“But . . . why?”

“I don’t know that either.”

She shook her head. “This is absurd. You’re the police. How can anyone stop you having a simple blood test done?”

“By destroying the body and all the blood and tissue samples.”

“You’re kidding!”

“This morning. They incinerated everything.”

Margaret simply couldn’t believe it. “That’s not possible. I mean, in most US states all toxicology specimens are held frozen for one year. Five in homicide cases.”