They reached an unassuming door in the far wall, through which Hawkins led her colleague into the main operations room. Four faces glanced up from various desks, her team having answered the call to be here when she returned. Everyone gathered around the investigation board at the front of the room.

‘Thanks for coming.’ Hawkins took her position front and centre, glancing across at Amala who was now standing, but still working away at something on her computer screen.

‘Sorry, ma’am.’ The sergeant raised an apologetic hand. ‘Be right with you.’

‘Quick as you can.’ Hawkins addressed the whole group. ‘I’m sure by now you’ve all read Frank’s reports regarding our conversation with the local farmer who fired an air rifle at Chris and me near the church at Cold Christmas, as well as the new murder scene Frank and I attended in the early hours of this morning.’

There were affirmative noises as she caught Frank’s eye and turned in response to his nod, pleased to find printed photographs of the latest victim already up on the investigation board.

‘Good.’ She pointed at a blown-up image of the mark found under the body. ‘What you may not be aware of is the symbol’s provenance.’ Briefly she explained her visit to the SOCO’s ex-girlfriend, and the ominous meaning of the shape scratched into the floor, before looking at Chris. ‘Did you review the photographs from the previous murder scene?’

‘Yes, ma’am.’ Chris straightened like an army recruit. ‘Checked every frame, but there’s nothing like that in any of them.’

‘OK.’ She turned to Frank. ‘Any updates on our latest victim?’

‘Aye, Chief, just heard from the DVLA. The white Fiesta left at the scene is registered to Glenn Baker, a twenty-year-old student who lives with his parents in Grange Road, Watford, twenty-five minutes’ drive from the cottage where he was found.’ He held up a printed copy of Baker’s driving licence. ‘That’s definitely our kid.’

‘Good work, both of you.’ Hawkins was about to move on when she was interrupted.

‘Sorry, ma’am, this might be important.’ Amala had crossed the room and was collecting pages off the printer. She retrieved them and came forwards. ‘The techs found a link in the browser history on William Tennent’s Mac for a spiritualist chat room called Most Haunted dot com, except we weren’t looking for that sort of thing at the time, so nothing got flagged. Then the Cold Christmas thing came up. It took a while to search Colin Wilson’s laptop, because he was such a heavy user, while Kowalski used a shared PC at the house.’ She handed the pages to Hawkins. ‘They just confirmed the same link is present on each computer. Basically, it looks like all three victims had recently joined this forum.’