“No. That’s incidental. I did an autopsy once on the burned body of a woman pulled from a car wreck. Turned out she had a bullet in her. And that’s what killed her. The guy who’d shot her put her in the car, set it on fire and ran it off the road. He was trying to hide the fact that he’d shot her. He thought maybe the evidence would be destroyed in the fire.” She ran her hands back through her hair. “You see what I’m saying?”

Li thought about it. “You think the killer was trying to destroy evidence?” He paused. “Evidence of what? Chao hadn’t been shot, or stabbed, or had his neck broken. He had a bump on his head and sedative in his blood. If the object of the exercise was to try and hide that by burning him, it wasn’t very successful, was it?”

Margaret’s mind was racing. But it was racing in circles. “No,” she had to concede. “No, it wasn’t.” She felt as if she had held something precious and elusive in her grasp for just a moment, and then lost it again. And now it was like some half-remembered face that lurks in the memory somewhere just beyond recall. “Hell, I don’t know,” she said, deflated. “There’s something there. Why don’t you take me on a guided tour of this place? In fact, why don’t we retrace events, just as you think they happened?”

“What for?”

“For another perspective. Something you’ve already seen that I might see differently. Something you might see differently second time around.”

He was not convinced, but he shrugged and said, “Okay.”

So they put on Samson and Delilah again and went on to the balcony. Margaret sat in Chao’s seat, from where she had a view of the compound below. She had been tossing and turning in her hotel bed trying to sleep when Chao had been sitting here, she realised. It had all been less than forty-eight hours ago. He had still been alive when she arrived in China.

“He would have seen the lights of the car coming in,” Li said. “The elevator was off, so he would have gone downstairs to let his visitor in.”

“Let’s do it.”

They crossed the living room and Li put the CD on pause.

“We’ll be back up in a few minutes,” he told the officer in the hall.

They went into the stairwell and down five flights. The gate at the foot of the stairs was locked. “Don’t you have the key?” Margaret asked, irritated.

“No. The killer must have taken it to unlock the gate on the way out with Chao.”

“And locked it behind him?” It seemed unlikely, somehow.