‘We weren’t allowed in the toilet, but I had to take a piss. So I went out the back and did it there.’

‘On the bricks?’ Shaun said.

Aaron nodded.

‘What bricks?’

‘Those things—you know. Those piles of bricks. They hold up the buildings.’

The brick piers, I thought, and wondered if I should start hosing them down.

‘Are you a dog, Mr King?’ Shaun demanded.

‘No.’ A pause. ‘Sir.’

‘Well, you’re acting like one. Dogs piss on walls, not people.’ Before Aaron could do more than scowl, Shaun said, ‘Did you see anyone else while you were back there?’

‘’Course not.’ Aaron’s tone was contemptuous. ‘I was taking a piss. I didn’t want any perverts watching me.’

‘Sir,’ Shaun reminded him.

‘Sir.’

I couldn’t understand why Aaron had been brought to my office. What was the plan? That I would embarrass a confession out of him? Play good cop to Shaun’s bad cop?

I had to admit, Aaron looked guilty. He couldn’t meet my eye. He kept scratching and shuffling like someone tortured by regret.

I thought, Maybe it’s the drugs he was on.

‘Have you heard any other boys discussing this?’ Shaun asked.

Aaron stopped moving. ‘No,’ he growled, omitting the ‘sir’.

‘So there hasn’t been any talk?’ Shaun’s tone suggested he didn’t believe a word of it.

‘Maybe. I dunno. I don’t listen to those losers.’

‘Do you have any thoughts on who was responsible?’ As Shaun moved, the floor creaked in a vaguely threatening way. ‘Because this doesn’t make sense. I understand why someone might dump rubbish on my bed, or Mr Doyle’s. We’re making your life a misery. But why target Ms Ayres? All she does is clean up after you.’

Aaron said nothing. Shaun stopped next to him, tilting his head so that Aaron couldn’t turn away without looking scared. ‘What I’m saying, Darren, is we think the dropkick who did this might hold some grudge against her. And you’re the only one who falls into that category.’

Aaron’s head jerked up. ‘Me?’ He sounded genuinely perplexed.

‘Because you know each other.’

‘Bullshit!’ There was a touch of outrage in Aaron’s voice. I couldn’t tell if it was the outrage of someone falsely accused or the outrage of a teenager who’d been bracketed with a lame bit of background noise like me.

‘I used to be your teacher in Otford. When you were six.’ I was watching him closely when I said this, and caught something deep in his pale green eyes. A twitch. A slight recoil. ‘Don’t you remember?’

‘No.’ Too quick.

‘It wasn’t for long, but you made an impression.’ As he shook his head, I added, ‘That was before you changed your name.’