Singh and Sasha looked at each other. ‘I think I’m going to need to take those phones,’ Singh said.

Courtney looked dismayed, but Kian and Bradley were already rooting in their bags for the phones.

I can’t, Cassie said. I told you. I lost mine.

‘That was the phone you lost? Have you seen it since the weekend you went to Normanby Hall?’ Singh asked. I remembered that she had broken into Steve’s office because she thought her phone would be in there, and if she was right maybe he’d been trying to cover his tracks.

Cassie shook her head. That explained what she, Bradley and Courtney had been keeping from him the other night – the other two realised Cassie was talking about her second phone, her secret phone, and they couldn’t be the ones to share the secret.

‘Okay, if it turns up please let us know. Do any of you still have the messages from Joe on your phones?’

They all shook their heads.

None of us have had any messages since Leon went missing. When we realised it might have something to do with Joe, we deleted everything, Bradley told the detectives. I’m sorry, it was a stupid thing to do, but we were covering our own backs.

‘Don’t worry. We can get in touch with the service provider and see if we can get a record of the messages. If we find out who was messaging you it might help us to find out where Leon is, and who killed Mr Wilkinson.’

Whilst we knew that Steve had been posing as Joe, the kids didn’t, and Singh clearly wanted to keep it that way. I thought I couldn’t be shocked any further, but this new revelation had succeeded. Had Steve been posing as Joe to all of them in an attempt to find the perfect candidate for grooming? I felt sick at the thought.

The students were sent back to class but Sasha stayed in the room with us.

I feel like I’ve failed them, she told us, shaking her head slowly. She looked devastated that she’d missed what was going on. If I’d known sooner I would have come to you, but they’re good at keeping secrets. Bradley has it in his head that he and Kian need to keep a low profile, in case they’re split up or have to leave here and end up in some children’s home. They were born in London, but they came up here for school when they were taken into care, because none of the London schools had places at the time when they needed an emergency placement. This is home now, but Bradley still holds a fear of London as a whole, because the person who abused him is there, albeit in prison now.