I felt a churning sensation in the pit of my stomach. That’s who Joe was, and the other students were talking about him. Singh had told me Leon had been talking to someone online – I should have made the connection. I glanced at Sasha and she grimaced at me; neither of us had realised the significance of the conversation we’d had the previous day.

‘We’re doing our best to find out who Joe is. There’s a chance he really is who he says he is, but in this situation we have to assume the worst. The messages stopped abruptly on Saturday morning.’

So? Sasha signed, interrupting. That doesn’t mean that it had anything to do with Leon disappearing.

‘If you’d let me finish,’ Forest said icily, ‘you’ll see there is a connection. Leon arranged to meet Joe when he was on the trip at Normanby Hall.’

Liz and Sasha looked at each other, the social worker closing her eyes and shaking her head, but neither of them interrupted again.

‘According to what he’s told Leon, Joe lives in Scunthorpe, and when he found out Leon was going on this trip he suggested getting a bus up to the park and meeting him on Friday evening. The messages show that Joe didn’t turn up when Leon was expecting him to, but he apologised and said he’d meet him in the cricket pavilion at nine o’clock on Saturday morning instead. Leon replied to say he would leave the cabin before the teachers woke up, because it would be easier to get away then, and he’d be there waiting for Joe.’

Both Sasha and Liz looked at Forest expectantly but the DI shook her head.

‘What happened after that is anyone’s guess, because the messages end there. But we have to assume that whoever Joe is, they deliberately lured Leon out of the cabin and into the park, even when the snow was coming down heavily. Whoever it is certainly doesn’t have Leon’s safety in mind, and we’re now going to work on the assumption that Leon has been abducted. We also have to consider that Steve Wilkinson discovered what was going on, tried to bring Leon back, and was killed as a result.’

A chill settled on the room that had nothing to do with the weather outside. I waited for one of the detectives to speak, but they were silent, letting the full impact of what they had discovered sink in.

This is ridiculous, Liz told the detectives, bristling. We do a lot of work with the students on internet safety, there’s no way Leon would have done something so dangerous and foolish.

‘I’m sorry, but we have the messages,’ Forest replied bluntly. ‘Leon did arrange to meet Joe, whoever Joe is.’