Erika peered at the map.

‘The storm drain is a major tributary,’ Moss went on, ‘and over the past few days an enormous amount of meltwater from the snow and rain has seeped into the ground and will have rushed through the storm drain.’

‘Pushing anything with it, including a phone,’ finished Erika.

‘Yeah.’

‘So the phone battery is now dead, obviously?’

‘Nothing has been detected. It’s an iPhone 5S, and the network tells us that it will still broadcast its location to phone masts for five days after the battery has discharged – of course, that’s now passed.’

Erika looked at the map; she saw Moss had drawn a red line from London Road along to Honor Oak Park. It covered just over a mile and a half.

‘So, what? The theory is that the phone was chucked or dropped into a drain when Andrea was taken?’

‘Yeah. But it’s not a theory that DCI Sparks or Chief Superintendent Marsh want to hear. They’re convinced they have their man in Marco Frost, and they’re under pressure from Oakley et al to make a conviction. They’ve been through his laptop and there’s a lot of Andrea on there. Photos, letters he’d written to her, Google search history about places she’d been, and was going to . . .’

‘This is a major breakthrough, but why are you here, Moss?’ asked Erika, getting up to make more tea.

‘I’ve been there when we questioned Marco, and he is – was –

obsessed by Andrea. But, he just doesn’t seem like he’s got it in him. He also has very large hands. Isaac showed us the handprints on Andrea. And I don’t know, it’s not much more than a hunch.’

‘You don’t think he did it.’

‘I have doubts, but they are a hunch. I think that this phone could open up the investigation,’ said Moss.

‘Well, you’ve got to get a team down in that drain, to at least have a look,’ said Erika.

‘Yeah, but under whose authority, boss? I haven’t got any. Your hands are tied. It would cost a huge amount, plus the manpower involved, who would sign off on either of those right now? The team is now focusing resources towards the prosecution of Marco Frost.’

Erika thought. ‘Does anyone else share your doubts about Marco Frost?’

Moss nodded.

‘Peterson? Crane?’

‘And others. We’ve made copies of the files on Tatiana Ivanova, Mirka Bratova and Karolina Todorova.’

She handed them to Erika, who flicked through, looking at the photos of the girls – all lying on their backs, naked from the waist down, their wet hair plastered to their pale faces. Fear in their eyes.

‘Do you think he deliberately leaves their eyes open?’ asked Erika.

‘Possibly.’

‘If it is the same killer, how the hell does Andrea fit in with this?’

‘Whoever it was ventured out of their comfort zone? She’s a different kind of girl,’ said Moss

‘Only because she was rich. The girls are all similar. Dark, beautiful, good figures.’

‘Do you think Andrea was working as a prostitute? Did you see the stuff in the papers?’

‘She didn’t need the money. I think first and foremost she saw sex as a thrill,’ said Erika.

‘The thrill of the chase,’ finished Moss.

‘What if Andrea had fallen for the man who is doing this? She’s attracted to dark, handsome men.’

‘But what about Ivy Norris? Her death bore hallmarks of the previous killings, but she doesn’t fit the pattern. She wasn’t young. Or attractive like the rest of these girls.’

‘Maybe it wasn’t about that? She shares the common thread that she was a prostitute. What if she saw Andrea with the killer, in the pub? And she was killed to shut her up.’

Moss had no reply to this.

Erika became aware that they were sitting in the dark. The sun had set. Erika went to the kitchen drawer and took out the note she’d received. She came back and placed it in front of Moss on the coffee table.

‘Shit. Where did you get this?’ Moss asked.

‘I found it in my pocket.’

‘When?’

‘Just after I was suspended.’

‘Why didn’t you hand it in?’

‘That’s what I’m doing now.’

Moss looked up at Erika.

‘I know. Jeez, this means we’ve got a serial killer out there,’ said Erika.

‘A serial killer who got close enough to put this in your pocket. Do you want me to arrange for a car outside?’