I could tell he was reluctant to answer, but I felt that I deserved to know, so pushed him for information.

‘It looks like he had his throat cut,’ he said eventually.

‘Same as Steve?’

He nodded. ‘Pretty much. It’s the same MO, only a week after Steve’s death, so the most likely conclusion is that they were probably killed by the same person.’

A shiver ran through me as I realised that everyone who had been in the building was in the hall with us, and that would include the murderer. If Leon had seen who killed Steve, and now they’d murdered Saul, then he was in danger: they might be coming for Leon next.

‘I assume there’s no CCTV or anything?’

‘The one outside the residence still isn’t working,’ he said. ‘But we’re checking all the other external cameras in case someone came into the school this morning who we’re not aware of.’

This put paid to the theory that Leon killed Steve and ran away in order to prevent himself being caught, unless he’d snuck back into the school to kill Saul. That seemed to be a particularly risky move, however, and there was no obvious motive for Leon to kill Saul. I thought the police would be forced to go back to looking at Leon as just a victim again and not a suspect.

‘Did you find out what it was Saul wanted to show you?’

Singh shook his head again, looking annoyed at himself. ‘No, I was looking for him when you found me and told me what had happened. We’re going to get our techs searching all his files, but we have no idea what they need to be looking for. It could take weeks.’

I felt sick. Saul must have found out who killed Steve, and possibly why they did it, but the murderer got to him before he could tell the police.

The snow continued to fall outside, building up against the window panes and obscuring the view. Singh and Forest had gone out of the room to form a plan of action, and I felt completely useless. A couple of the PCs organised drinks and fruit to be brought from the school kitchen and handed out – the last thing they needed was for any of the staff or students to get dehydrated.

After another half hour, Singh reappeared and came over to me.

‘I need to speak to Liz Marcek, if you wouldn’t mind asking her to join us outside.’

I crossed the hall and approached the deputy head, where she was standing with her arms folded, worry etched onto her face.

The police want to talk to you, I told her, and indicated where Singh had left the room and was waiting in the corridor outside the hall.