I said, “That was Detective Curran’s guess, too. Would a mustelid fit with whatever was going on in the attic?”

The padlock clicked, and Tom pushed the door open. The house was cold—someone had switched the heat off—and the faint tang of lemon in the air had faded: instead it smelled of sweat, the plasticky chemical scent of crime-scene overalls, and old blood. Cleaning up crime scenes isn’t in our job description. We leave the debris behind, the killer’s and our own, until the survivors either call in a professional crew or do it themselves.

Tom headed for the stairs. “Yeah, I read your vic’s Wildwatcher thread. He’s probably right about ruling out mice and rats and squirrels—they’d have been all over the peanut butter. First thing I thought: hey, any of the neighbors got a cat? A couple of things don’t fit, though. A cat wouldn’t just take the head off that robin, and a cat wouldn’t spend a lot of time hanging around the attic without giving itself away—meowing to get down through the attic hatch, or something. They’re not careful about humans the way wild animals are. Plus, your vic said he smelled something musky, yeah? Musky or smoky? Doesn’t sound like cat spray to me. Most of the mustelids, though: yeah, they’ll let off a musky smell.”

He had dug up a stepladder somewhere and put it on the landing, under the hatch. I found my torch. The bedroom doors were still half open; I caught a glimpse of Jack’s stripped bed.

“Careful,” Tom said, swinging himself up through the hatch. Above us, his torch came on. “Pull left, yeah? Don’t want to hit this.”

The trap was on the attic floor, just a few inches to the right of the hatch. I had only seen it in pictures. Solid, it was more powerful and more obscene, wicked teeth splayed wide, torchlight sliding in smooth arcs along the jaws. One look and you heard it, the savage whisk of air, the bone-crunching thud. None of us moved closer.

A long chain straggled across the floor, anchoring the trap to a metal pipe in a low corner, among dusty candlesticks and outgrown plastic toys. Tom nudged the chain with one toe, keeping his distance. “That,” he said, “that’s a leghold trap. Nasty bastards. A couple of extra quid gets you one with padding or offset jaws, so it’ll do less damage, but this one’s old-style, none of your fancy stuff. The animal goes in after the bait, puts pressure on the pan, the jaws bite down and they don’t let go. After a while the animal bleeds out or dies of stress and exhaustion, unless you come back and get it. It could maybe gnaw its own leg off, but it’d probably bleed to death first. This trap’s got a seven-inch jaw spread: it could handle anything up to, like, a wolf. Your vic wasn’t sure what he was chasing, but he was bloody serious about getting it.”