‘Samira, thank you for coming to speak to us,’ Singh replied, unfazed by the attitude. ‘We don’t think you’ve done anything, but you’re the person who can tell us the most about Leon. Would you like to sit down?’

Did they send you because you’re Asian too? They thought I’d be a good little Muslim girl and respect my male superiors? Samira replied, still standing.

Singh laughed. ‘Well, I’m half Indian, half White Scottish. My dad is a Sikh and my mum has no interest in religion, so I don’t think that strategy would really work.’

The corner of Samira’s mouth twitched but she fought off the smile and gave a big theatrical sigh instead. Throwing herself onto a chair, she shuffled her skirt down from where it had ridden up. Her brother sat down next to her and pulled out his phone, but then hurriedly put it away again when it earned him a frown from both the detectives.

Okay, what do you want to know? she asked, doing her best to look bored.

‘Firstly, we really need to know if Leon has been in touch with you since Saturday.’

She shook her head. Nope, not heard from him.

I could see Singh watching her face carefully as she signed – even though he couldn’t understand BSL, he could still observe her body language and facial expression for indications that she could be lying or hiding something.

‘Has he ever talked to you about being unhappy at school?’

Everyone’s unhappy at school, Samira replied, with an over-the-top roll of her eyes. Why would anyone want to be here when they could be chilling out and doing whatever they want? But he wasn’t depressed or anything, he put up with it same as everyone else.

‘Can you think of anywhere that’s particularly special to Leon, where he might go if he was worried or scared?’

Samira appeared to think for a moment. I don’t think so. I mean, he lives at school. Where else has he got?

Forest nodded, while Singh made notes.

‘What about anything in Leon’s personal life that might have affected his mood?’

Samira looked wary. What sort of thing?

‘Anything that happened recently that could have upset him, or made him behave out of character? Anything he might have been worried about?’

The girl inspected her nails for a moment, which were coated in a sparkly turquoise gel polish. I imagined she was breaking school rules by having them done like that, but I also suspected she didn’t care.

There might have been something, she began, then shook her head.

‘Samira, tell them,’ her brother said, speaking and signing at the same time. ‘Even if it’s small, you need to tell them.’ I got the feeling he was saying this to make her hurry up, rather than to emphasise the importance of her being open and honest.