“I mean, it would have been easier with two.”

Li nodded. “Yes, but there’s something very . . .” He struggled to find the right word. “. . . individual, almost eccentric, about this. It just feels to me like a single twisted mind at work.”

One of the forensics team called them through to the hall. He was crouched outside the kitchen door, scraping carefully at the carpet. “Patch of blood,” he said. “Looks quite fresh, too. Spectral analysis will tell us just how fresh.”

Qian looked at Li with renewed respect. “If that’s Chao’s blood, it looks like you could be right, boss.” Then he grimaced. “Trouble is, it doesn’t really get us any closer to the killer.”

“Everything we know gets us closer to the killer,” Li said evenly. “Time we talked to the street committee.”

V

Liu Xinxin, chairwoman of the street committee, was a small, nervous, skinny woman of around sixty. She lived in a ground-floor apartment in Chao Heng’s block. Her greying hair was drawn back in a tight bun from a delicately featured face, she wore an apron over a grey smock and a pair of black baggy trousers that stopped six inches above her ankles. Her hands were white with flour. “Come in,” she said when she answered the door. She brushed a rogue strand of hair away from her face and left a smudge of flour on her forehead. She led them into the kitchen where she was preparing dumplings for the family meal. “You’ve come at a bad time. My husband will be home soon, and then my son and his wife.”

Li nodded. “There is never a good time to come about death.”

There was a loud crash from another room, a skitter of giggles, and two boys of pre-school age chased one another, shouting and screaming, through the hall. “My grandchildren,” Liu Xinxin said. And then she added, quickly, as if they might suspect her family of being politically incorrect, “The elder boy is my daughter’s.” A shadow passed across her face. “She died in labour and they had to cut the child out of her. My son-in-law couldn’t deal with her death, or with the child, so my son and his wife adopted him.”