‘I doubt it, to be honest. Even if they’re not put off by a murder and manage to make it through the snow, they’ll have to fight through the journalists at the gate.’

At that moment, the deputy head appeared, so I interpreted Singh’s request and she nodded.

I still don’t believe any of my staff could be capable of this, you know, she told him with a haughty look. There must be some other explanation.

Singh didn’t answer, and I couldn’t really blame him.

As time went on, staff who had managed to get home the previous night began to drift in. When it got to nine, Singh went round the hall and checked every single name against his list. Every staff member had come to work that day.

‘I don’t know if this is a good thing or a bad thing,’ he muttered to Forest. ‘If someone had done a runner at least we’d know who we were looking for. This just means they’re cocky enough to believe nobody will work it out.’

‘And when they’re cocky, they’ll make a mistake,’ Forest said smoothly. She didn’t seem to share Singh’s frustration at the situation, and I wondered how she managed to stay so calm when there was a killer practically thumbing his or her nose at them.

As they had suspected, none of the students arrived for school that day, and Liz Marcek told the detectives she had been fielding emails all through the night and into the morning. Parents were demanding to know what was happening, if the school would be closing, and Liz didn’t have any answers for them.

I don’t know what I can tell them, she had told Singh angrily. Until you tell me what’s going on, I can’t do anything.

‘I wish she understood that, right now, the reputation of this school is not our first priority,’ he grumbled to me afterwards.

As we were walking out to the car park, a car pulled up and Jane Villiers got out. She was an imposing presence, and I could see why she had been the head teacher here for so long – it was almost as if the school suited her.

‘I need to speak to you,’ she said to Singh. ‘Immediately.’

She was lucky she had caught us rather than another member of staff. Singh introduced her to Forest, then ushered her inside, where we were met with a startled Liz Marcek.

Jane. What are you doing here?

Reporting a motive for murder, Jane signed back. Liz took a step back, indicating that Jane and the detectives should go into her office. For a moment, the ex-head teacher hesitated, as if she wanted to use her old office, but then thought better of it. I hung back, but Forest ushered me inside with them, leaving Liz standing in the corridor, frowning.