I’d spent two hours outside his house, had gone to Keighley town centre, to the mill again, walked the streets and parks surrounding his property, before returning to his house for another three-hour sit-in, and he hadn’t come up for air once. I’d phoned Seiger and Sten and, when one of Jacob Pierce’s staff had picked up, I’d pretended that I’d recently done some work with Mills but had lost his contact details, and they told me they’d never heard of him. It had sounded genuine too, the woman’s confusion hard to fabricate, so – as a final move – I’d tried phoning Mills’s mobile. It went straight to voicemail.

After I rang off, I started to realize something: because whatever Mills was doing for Jacob Pierce was completely off the books, so was anything that happened to him as a consequence. I’d looked at his empty house, its shutters closed, and had started to wonder if someone had discovered what he’d done for me. I was so conflicted about Mills, I didn’t even know how to process the feeling. I still wasn’t sure if I could trust him. And yet he’d given me the alarm code and the key to Pierce’s hidden room.

He’d led me to the clothes.

The conversation between Patrick and Freda.

I looked down into my lap, at his handwriting, the sequence he’d written on the reverse of the Dictaphone: G76984Z. I still hadn’t worked out what it meant, but he’d put it there for me to see. It was there, too, because he didn’t want to be found out. That was why the clues were so subtle: he was trying to fly low.

But maybe they hadn’t been subtle enough.

Someone opened the front door of Melia Griffin’s house: it was her fifteen-year-old daughter, her face fixed on the screen of her phone. I watched her go, head down, still staring at her mobile, and then – ten seconds later – her mother came to the door, opening it a sliver and looking out to where the girl was going. She didn’t want her daughter to see her, to know that she was checking on her, conscious of embarrassing her. The girl was long past waving goodbye as she walked away – didn’t even look up from her phone – but her mum watched her all the way to the end of the street and, when she was gone, Melia lingered there for a second. It was such a delicate and natural moment, a mother still finding it hard to let go, even now, that – for a second – I lost sight of my reason for being here, thinking of my own daughter instead, almost twice the age of Melia’s. I pictured Annabel, and then Olivia. I wondered what they were doing.

And then the door closed again.