He locked up his car and led the way. July had been so hot that the trail had baked hard, a spider’s web of cracks levering open the ground beneath them. It was still early – not yet 7 a.m. – but it was light, the sky streaked amber and pink, and, as they walked, Callson remarked on the unexpected clarity of the morning. She listened to him talk about the weather, about the colour of the mountains in the sun, about how beautiful the city looked on days when it wasn’t sitting under a blanket of smog, and she thought how different he seemed from the men she worked with, how unlike a cop he sounded. She’d never met Callson before, and had only spoken to him briefly on the phone the previous night, but there was something benign about him, in his manner, that made her feel instantly at ease in his company. It was the total opposite of how she felt most of the time in the squad room.

‘How long you been a detective?’ he asked her, his fingers still clamped on the binder. She noticed he didn’t wear his wedding ring on his hand, but on a band around his neck. He had a shirt on but no tie, and the ring swung gently in the V at his collar.

‘Since ’78,’ she replied.

‘You enjoy it?’

‘Yeah,’ she said, but then thought of the body she’d found in the tub the day before, of the panic that had gripped her on the way out this morning. ‘Most of the time.’

‘That’s about as much as we can hope for, right?’

‘Right,’ she said, and watched him for a moment, just ahead of her, his breath coming more quickly now but the smoothness of his gait hardly changing. Whatever was up with him, whatever it was that she’d glimpsed back at the cars, it definitely wasn’t physical. ‘What about you? How long have you been working for the LAPD?’

‘I joined in 1950.’

‘Thirty-five years. Wow.’

‘Wow is right. A long time. It’s not technically thirty-five: there was three years in Vietnam somewhere in all of that and, believe it or not, I actually retired at the end of ’83 and spent last year playing golf. But then they got so overloaded with all the shit that’s going on in this city at the moment that they came back to me in February with a better deal – more money, not so many hours. So here I am again.’ He smiled at her. ‘I actually know a couple of the guys over there with you in the Detective Bureau. We worked the Hillside Strangler back in the day.’

‘You were on the Strangler team?’