Typical. Singh looked to the PCs to explain what they knew so far.

‘We got an automatic message that the alarm had gone off, so we responded and found a student had broken into the head teacher’s office.’ They glanced at Cassie as they said this. ‘The staff hadn’t been aware of the alarm.’

‘Isn’t the alarm linked up to the residence?’ Singh asked.

It should be, Liz replied, but it didn’t go off. I assume it must be faulty. I’ll get an engineer in to look at it as soon as possible.

I immediately wondered if it was simply a malfunction, or if someone had disabled it.

‘Why are you here, Miss Marcek?’

It’s our policy here that teaching staff take occasional shifts in the residence, in order to foster stronger relationships with the students. Tonight was my turn.

Singh looked surprised that the deputy head had included herself on the rota. ‘Did Steve Wilkinson take shifts in the residence too?’

She nodded. Sometimes. Not regularly, though.

A chill ran down my spine at the idea of the man who had been grooming Leon supervising vulnerable children overnight.

Throughout this conversation, Cassie had been sitting with her arms folded and her head down, a sullen expression on her face. She was dressed in purple pyjamas and had fluffy slippers on, so she had clearly crept back into the building after the staff thought she’d gone to bed.

‘Thank you, I’ll take it from here,’ Singh told the two PCs, and they looked relieved to be dismissed.

Taking a chair, Singh sat down opposite Cassie. ‘Now Cassie, what’s been going on?’

It took a moment for me to get her attention to sign the question to her, but when I did she sighed deeply.

I was looking for something, that’s all.

‘What were you looking for?’

She chewed her lip for a moment before replying.

I lost my phone. I thought maybe Mr Wilkinson had taken it.

‘Why would he have taken it, Cassie?’

She shrugged but didn’t reply.

Liz shook her head. Cassie, how did you even get in here?

There was a pause, in which Cassie looked at all of us in turn. A slow smile spread across her face. I’ve got a key, she signed.

A key? How did you get a key?

But Cassie refused to say anything else and couldn’t produce the key when she was asked about it, saying she must have dropped it.

Liz pulled Singh aside. I honestly can’t believe that she got hold of a key to the head teacher’s office. I must have left it unlocked by accident, and then when she opened the door, the motion sensor set off the alarm.

‘I think we should escort her back to the residence now,’ Singh replied. ‘I’m assuming you don’t want to press charges?’