Waiting. My life has become one long wait. I’ve never felt more impotent in my life. Mark and Jake wouldn’t let me help with the search after Billy went missing. They said I needed to stay at home. ‘Someone needs to man the hub,’ Mark said. I don’t think that was the real reason he told me to stay behind. I think he was worried I’d break down if we found anything awful. He would have been right but I can’t continue to sit and wait. I need to find Billy.

‘I’m fine, Dad.’ I force a smile. ‘But I could do with some fresh air. Are those fliers up to date?’ I point at the teetering pile of paper under the windowsill.

‘Yes.’ Mum nods.

‘Could we go somewhere and hand them out? Maybe … the train station?’

Last week I went through Billy’s things. I’ve been through them a hundred times since the police searched his room – the familiarity is comforting – and I found an exercise book at the bottom of a pile on his bookshelf. He’d only written in it twice. On the first page he’d half-heartedly attempted some maths homework and then crossed it out and written underneath, Maths is shit and Mr Banks is a wanker.

That made me smile. It was something I could imagine him saying to Mark when he’d ask how Billy was getting on with his coursework. Billy knew it would push his dad’s buttons but he’d say it anyway because he liked winding him up. I’d tell Billy off for swearing but it was always an effort not to laugh. Poor Mark.

After I’d read what he’d written I found a pen and wrote underneath it, No swearing, Billy. The tightness in my chest eased off, just the tiniest bit. So I kept on writing. I wrote and I wrote until I had cramp in my hand. It was so cathartic, so freeing to be able to cry, alone, without worrying that my grief might upset Jake and Mark.

I almost missed the other thing he’d written in the book. I only spotted it when the back cover lifted as I put it down. He’d graffitied the inside and scrawled Tag targets in thick black marker pen:

– Bristol T M (train?)

– The Arches

– Avonmouth

I couldn’t believe I hadn’t spotted it before, not when I’d been through Billy’s things so many times, and I immediately rang DS Forbes. He wasn’t as excited as I was. He told me they’d looked at the CCTV at the train station when Billy was first reported missing and they’d checked out Avonmouth and the Arches as they knew he hung out with his friends there. But what if they’d missed something? Something only a mother could spot?