“Jason Mott?”

“Yes. Here. That’s me.”

I stare down at the young man who stands below me ankle-deep in the mud of the banks of the Thames. He has sandy hair that hangs in curtains on either side of a soft, freckled face. He’s wearing kneehigh rubber boots and a khaki gilet with multiple pockets and is surrounded by a circle of gawping people. I go to him, trying to keep my shoes away from the mud.

“Good morning,” I say. “I’m Detective Inspector Samuel Owusu. This is Saffron Brown from our forensics team.” I see Jason Mott trying very hard not to look as if he is excited to be in the presence of two real-life detectives—and failing. “I hear you have found something. Maybe you could explain?”

He nods eagerly. “Yes. So. Like I said on the phone. I’m a mudlarking guide. Professional. And I was out here this morning with my group and this young lad here”—he points to a boy who looks about twelve years old—“he was poking about and opened up this bag.” He points at a black bin bag sitting on some shingle. “I mean, rule number one of mudlarking is no touching, but this was just sitting there, like someone had just dropped it there, so I guess it was OK for him to open it.”

Although I know nothing of mudlarking rules, I throw the young boy a reassuring look and he appears relieved.

“Anyway. I don’t know, I mean, I’m no forensics expert . . .” Jason Mott smiles nervously at Saffron, and I see him flush a little. “But I thought that they looked like they might be, you know, human bones.”