No, don’t be silly. If we pressed charges every time one of the students in the residence came up with a silly prank we’d need a police officer here all the time.

We walked back over to the residence, where the lights were on in the sitting room. Bradley and Courtney were waiting for us.

What happened? Bradley asked.

Is it something to do with Leon? We saw the police. Courtney pulled her dressing gown round her, obviously self-conscious at the sight of us.

No, nothing to do with Leon, Liz told them. Go back to bed. She had a sour look on her face at the two of them sitting there in pyjamas, which made sense now I knew their relationship had nearly cost the school its reputation.

No, Bradley replied, standing his ground. I want to know what happened.

I was looking for my phone, what’s the big deal? Cassie flung herself down onto the sofa. You didn’t have to call the bloody police!

‘Cassie, you set the alarm off,’ Singh explained. ‘The school is linked directly to the police station. They had to come. You’re lucky we’re not going to arrest you.’

What were you doing, you idiot? Bradley asked her.

I’m not an idiot, she replied, her jaw clenched.

To my surprise, Bradley leant over and gave her a hug. You’re right, you’re not. I’m sorry. But what do you mean, you were looking for your phone?

Liz interrupted. Cassie seems to have got it into her head that Mr Wilkinson might have taken her phone. Did he confiscate it while you were on the trip? She directed this question to Cassie.

No, but I thought … Cassie didn’t finish and let her hands drop to her lap.

You had your phone on Saturday, on the trip, Bradley told her.

Cassie nodded.

Well, didn’t you have it in the bus on the way back to school? You showed me the post about Leon going missing and that video of the dog. You know, the one that couldn’t catch the ball?

Cassie stared at him for a moment, as if she was willing him to understand something. Yeah, you’re right. But …

A look passed between the two of them, and Bradley’s expression changed as Cassie’s meaning dawned on him. He turned to Courtney, who frowned, but then she obviously understood too and her eyes widened.

Should we go back to bed now, Miss Marcek? Bradley asked.

The deputy head looked puzzled at this sudden change in attitude. Yes, I suppose so.

‘No, wait a moment,’ Singh said. ‘What is it that you three aren’t telling us?’

The teenagers all put on their most innocent expressions.

Nothing, sir, Bradley replied, laying it on thick.