‘We’re part of it somehow, no doubt about it. I was talking to Professor Layton.’ Bloom saw Jameson nod his recognition. He and Layton had met a handful of times. ‘We talked, and to design this game would be a phenomenal undertaking. It would need lots of money and lots of time. And technical skill. I’d be amazed if it’s the work of one individual.’

‘Do psychopaths do working together? Aren’t they just self-centred egotists out for themselves?’

‘That’s been the predominant theory. But what if it’s wrong? Or something’s changed?’

‘They’ve evolved into pack animals?’

Bloom gave him a dismissive look. ‘Evolution is not that quick. This is motivated by something more human.’

She dialled in to Barker’s conference call and put the phone on speaker so Jameson could listen too. After a few moments the music stopped and DS Phil Green’s voice filtered through.

‘Afternoon, both. It’s just me, Kaye and Raj today. The others have all been called to an incident in town.’

Jameson raised his eyebrows at Bloom. It seemed their investigation was no longer the top priority.

‘Hello, everyone,’ said Bloom. ‘So here’s what we know so far. One hundred and nine people have received a birthday card and taken up the dare. Craig tells me he has now identified four players who have returned home after a month or so, including Clive Llewellyn and Faye Graham, although after killing her husband Faye has disappeared again. All the others have been missing for anything from a few weeks to over a year. We’ve had no one come forward to say they received a card but didn’t take up the dare.’

Bloom paused to see if anyone would dispute that. They didn’t.

‘We’re bringing in the other two returned players for interview,’ said DS Green.

‘Good,’ said Bloom. ‘Although I expect they’ll be as slippery and uncooperative as Llewellyn was.’

‘Don’t underestimate us.’ DS Green sounded offended.

Bloom didn’t rise to it and continued her briefing. ‘Then last Friday, Jane Reid – the daughter of one of our missing players, Lana Reid – also went missing, near her school. She was caught on CCTV at King’s Cross station on Saturday morning, but no one has seen or heard from her since then.’

‘That reminds me,’ interrupted DC Raj Akhtar. ‘A Thomas Lake was in touch yesterday. He’d seen the appeals for Jane Reid. I’ll email over his number. It sounds legit, but he’s not a criminal. He’s a dentist in Manchester.’

‘What?’ Jameson looked up from the desk.

Bloom turned to him and spoke quietly so that only he would hear. ‘Are you still under the impression that Lana’s a trustworthy source, Marcus?’ Then she said, ‘Thanks, Raj, we’ll look into that.’