‘Don’t be. I’m glad I heard it. He’s poisonous, and I don’t want anything to do with him, but I’m glad I know exactly what he said about me. I can’t believe I ever thought he might have changed.’

‘Come on,’ Singh said, taking my hand to help me up off the floor. ‘I need to go to the school to collect those notes from Cassie. Are you up to interpreting?’

I nodded and followed him. As we walked out to the car park, he hesitated. ‘Do you mind driving? My car wouldn’t start this morning so I got a taxi here.’

We got into my car and set off for Lincoln, not speaking, both deep in our own thoughts. I was turning everything over in my mind when all of a sudden something struck me.

‘How did you find out about the messages between Joe and Leon in the first place?’ I asked Singh.

‘What?’ he said, coming out of a daze. ‘Oh, we had his phone number so we got the network to give us access.’

‘But how did you get that number? Who gave it to you?’

He paused. ‘I can’t remember. One of the staff. Why?’

‘How did they know about that phone?’

Singh didn’t reply, so I tried to explain my thinking.

‘The phone Leon was using to message Joe was his second phone, his secret one. Nobody knew about those phones except for the students.’

‘And the person who gave them the phones,’ he said quietly. ‘Shit. How did we not pick up on that?’

‘Whoever gave you that phone number knew about Leon’s secret phone,’ I said. ‘Which means they were the one who planned this whole thing, and they gave you that number instead of his usual number, because they wanted you to find those messages. They’d been setting Steve Wilkinson up, building up the evidence for months to destroy his life and his reputation, and now they’re letting you finish it off for them.’

Singh pulled out his phone and made a call. ‘I need to get someone to check the interview records and find out who gave us that number,’ he told me as he dialled.

I tried to concentrate on the road, but I could feel the tension vibrating off him as he spoke to someone at the station.

‘Okay, text me the home address.’ He hung up, then a moment later his phone beeped and my heart picked up its pace.

‘Change of destination,’ Singh said, then looked at me, remembering who was driving. ‘Shit. You can’t come with me.’

‘Do you think Leon will be there?’

‘Possibly.’

‘Then tell me where to go. You can’t waste time going back for another car,’ I told him, and he gave in, telling me where to go.

‘Where is this place?’ I asked, looking at the address he’d typed into my satnav.