Odontology had proved just as worthless as everything else: there was no match for the teeth, and so far no indication that Wilzon had received treatment at any clinic in Los Angeles. Jo had started to send out teletypes to agencies further afield, in an effort to see if Wilzon had come from somewhere else in California, but it was a long shot, she didn’t expect to get any hits, and she wasn’t convinced that that was where the answers lay, anyway. Forensics believed it was much more likely that Wilzon just hadn’t attended a dentist regularly, or perhaps at all. Chen had said that, judging by the condition of the skin, bones and internal organs, Wilzon was in his early to mid twenties, and during the transition from high school to college it often happened that as kids became adults, and moved away from home, they forgot to get their teeth checked regularly. Or perhaps, as Jo believed, there was another reason his teeth came up blank.

He never went to a dentist in America.

Because he wasn’t American.

From her in-tray, she took a sheet of dot-matrix printer paper that had been mailed over to her by Paolo Caraca, the owner of Caraca BuildIt. It was the details of all thirty-six members of staff he’d employed since 1982, when he’d bought out and changed the name of the supplies yard. Including former members of staff as well as current ones was more than Jo had asked him for so she’d spent the previous day running background checks on all of them. As much as she’d appreciated the gesture, though, it was still a dead end: none of his staff, former or current, had a record. A few had some minor traffic violations, but nothing to raise the pulse. What had been more interesting than the names, though, was what else she’d found out about Paolo Caraca’s business: it dealt in the supply of corrosive chemicals for industrial use – and one of them was muriatic acid. He told Jo that, at any one time, he could have as much as six hundred gallons in the yard, so she’d asked him to do a stocktake to ensure all containers were accounted for. He hadn’t liked it, because he felt he’d already done her a big favour with the employee list, but he’d agreed to do it anyway. Now she was waiting for the results.

She felt someone moving her chair.

Taking off her headphones, she swivelled around and could see that it was Lieutenant Hayesfield: he was walking past, clicking his fingers at her and pointing towards his office. Jo put the headphones down and looked at the clock. She’d lost all track of time. It was after 9 a.m. and the squad room was now full.