‘ . . . where there’s increasing concern amongst parents and volunteers about children being groomed into taking part in flash mobs. The police say these gatherings, which typically involve spontaneous music and dancing, may conceal criminal acts, and are involving children as young as ten.’

‘Bloody pond-life,’ Dan muttered.

‘We’ve long been familiar with the idea of grooming being something which paedophiles do,’ Carly continued, ‘but the police tell us that the same behaviour is being used in places like this,’ she gestured to the building behind her, ‘to lure children and vulnerable adults into breaking the law.’

‘Let’s hope this helps to get the message across,’ I said.

I left the broadcast and approached the board.

Alexej had written up the key developments.

- UnSub

- Kenny, Artem, Indra & Marta

- LfA

- Who are Frazer & John?

- Ali’s address

‘Jackie’s on her way and said to start without her.’ I pointed at LfA on the board. ‘Let’s begin with Agnieszka’s husband, Olaf Strozyk. Does his alibi check out for Friday?’

‘Yes.’ Dan got in first, his face tight with determination. ‘His PA confirms he was in the office all day and was still working when she left at six.’

‘What I don’t understand is, the fire was yesterday. Why wait a day and then call in?’ The photos of the burnt-out shop stared back at me from the board. Two lives had been snuffed out with the strike of a match. ‘The analysts still can’t identify the caller so there’s nothing to suggest whether the person actually represents LfA, or whether they’re trying to drop LfA in it.’

‘Is there no cell site data from the phone call?’ Shen’s eyes shone with hope.

‘No.’ Alexej had been following this up. ‘The voice sounds female but whoever made the call used voice distortion software and put it through a router so that the location bounced every few seconds.’

‘That’s not an amateur.’ I felt my heart sinking. ‘That’s someone who knows their technology.’ Olaf had been hopeless with his phone when we interviewed him, and hardly fell into the tech-savvy category. ‘I can’t see why Olaf would make the call himself when it drops him in it.’

‘The thing is, most people use anonymous usernames on the internet, so it’s hard to establish who’s responsible for what.’ Alexej was checking his screens. ‘Going on their company records, LfA seemed legitimate when Olaf was in charge. “Based on socialist principles . . . peaceful protests . . . affordable housing for everyone” . . .’ He was reading off his monitor. ‘They didn’t oppose all development, just gentrification.’ He was shaking his head. ‘I know people behave recklessly at university but given Olaf was planning to train as an accountant, he’d have been a bit silly to have got involved with anything criminal, surely?’