After two minutes talking to Andrea Hertz, Patrick knew she wasn’t their woman. She nervously invited them in to her tiny flat and offered them a cup of tea. Not wanting her to know the real reason for their visit – as it was, at this point he merely wanted to scope her out – Patrick said they’d had reports of teenagers causing trouble in the area and wanted to know if she’d had any problems. As she replied, stumbling over her words, his eyes fell on the framed photographs of two smiling children, a gap-toothed girl and cheekily grinning boy, on the sideboard.

Andrea Hertz was like a walking corpse, her spirit as emaciated as her flesh. Her hair was white; she looked twenty years older than her true age. Nothing like Bowie’s description. Carmella asked if she could use the toilet while Patrick chatted to her, so she could have a quick look round. When she returned she subtly shook her head and they left.

‘That poor, poor woman,’ Carmella said as they got back into the car.

‘Her poor children.’

They didn’t talk about it any more on the way to the address they had for Sharon Fredericks, a small terraced house on an estate on the outskirts of Richmond. The sun was shining again, the air clear and fresh following the earlier storm. As they stood outside the house waiting for someone to come to the door Patrick felt a tingle in his veins. They were on the right track now. He felt sure.

But there was no response.

He pressed the doorbell again and waited. Nothing.

‘Wait here,’ he said, pushing open the side gate and going into the back garden. The grass was overgrown, daisies and weeds choking the garden. The curtains were drawn across the back windows, but through a side window he could see into the hallway. Mounds of junk mail were stacked up behind the door.

He went back round to the front. ‘Looks like she hasn’t been here for some time.’ He checked the time. Five o’clock. He felt torn: he was sure this was important but he was desperate to see Bonnie, especially after everything that had happened today.

As if she’d read his mind, Carmella said, ‘Why don’t I go back to the station, try to find a new address for Fredericks, and you can get back and see Bonnie before she goes to bed?’

‘I don’t know . . .’

‘Go on. It won’t take both of us to look up an address.’

‘Have I ever told you what a great partner you are?’

‘I don’t think you have, actually.’

‘Well, I should have. I’ll go and see Bonnie and then meet you back at the station. Unless you want to get home.’

Carmella put a hand on his arm. ‘I’ll see you later.’