Slowly, as if my eyes were only just adjusting to the dim light, I realized that all the dark patches and stipples that I had taken for shadows and rainwater were actually blood. It was everywhere: streaked across the floor, soaking the girl’s jeans, crusting her hands wrist-deep. I didn’t want to look at her face, at anyone’s face. I kept my eyes on her top and unfocused them so that the dark star swam and blurred. “Got footprints?”

“Zip,” Frank said. “Not even hers. You’d think, with all this dirt; but, like Sam here said, the rain. All we’ve got in the other room is a shitload of mud, with prints matching the guy who called it in and his dog-that’s one reason I wasn’t too worried about walking you through there. Same thing out in the lane. And in here…” He moved the torch beam around the edges of the floor, nosed it into corners: wide, blank sweeps of dirt, way too smooth. “That’s what it all looked like, when we got here. Those prints you’re seeing around the body, those are us and Cooper and the uniforms. Whoever moved her stuck around to tidy up after himself. There’s a broken branch of gorse in the middle of the field, probably came off that big bush by the door; I’m guessing he used it to sweep the floor clean as he left. We’ll see if the Bureau pulls blood or prints off it. And to go with no footprints…”

He handed me another evidence bag. “See anything wrong?”

It was a wallet, white fake leather, sewn with a butterfly in silver thread and swiped with faint traces of blood. “It’s too clean,” I said. “You said this was in her front jeans pocket, and she bled out all over her lap. This should be covered with blood.”

“Bingo. The pocket’s stiff with it, soaked through, but somehow this barely gets stained? The torch and keys are the same: not a drop of blood, just a few smudges. Looks like our boy went through her pockets and then wiped her stuff clean before he put it back. We’ll have the Bureau fingerprint everything that’ll stay still long enough, but I wouldn’t bet on getting anything useful. Someone was being very, very careful.”

“Any sign of sexual assault?” I asked. Sam flinched. I was way past that.

“Cooper won’t say for sure till the post-mortem, but nothing on the preliminary points that way. We might get lucky and find some foreign blood on her”-a lot of stabbers cut themselves-“but, basically, I’m not holding my breath for DNA.”

My first impression-the invisible killer, leaving no trace-hadn’t been far off. After a few months in Murder, you can tell One of Those Cases a mile away. With the last clear corner of my mind I reminded myself that, no matter what it looked like, this one was not my problem. “Great,” I said. “What do you have? Anything on her, other than she’s in Trinity and she’s running around wearing a fake name?”

“Sergeant Byrne says she’s local,” Sam said. “Lives at Whitethorn House, maybe half a mile away, with a bunch of other students. That’s all he knows about her. I haven’t talked to the housemates yet, because…” He gestured at Frank.

“Because I begged him to hold off,” Frank said smoothly. “I have this little idea I wanted to run by you two, before the investigation gets into full gear.” He arched an eyebrow towards the door and the uniforms. “Maybe we should go for a wander.”

“Why not,” I said. The girl’s body was doing something funny to the air in there, fizzing it, like the needle-thin whine the TV makes on mute; it was hard to think straight. “If we stay in the same room for too long, the universe might turn into antimatter.” I gave Frank his evidence bag back and wiped my hand on the side of my trousers.

In the moment before I passed through the doorway I turned my head and looked at her, over my shoulder. Frank had switched off his torch, but pulling back the brambles let in a flood of spring sun and for the split second before my shadow blocked it again she rose up blazing out of the darkness, tilted chin and a clenched fist and the wild arch of her throat, bright and bloodied and relentless as my own wrecked ghost.

That was the last time I saw her. It didn’t occur to me at the time-I had other stuff on my mind-and it seems impossible now, but those ten minutes, sharp as a crease pressed straight across my life: that was the only time we were ever together.

The uniforms were slumped where we had left them, like beanbags. Byrne was staring off into the middle distance in some kind of catatonic state; Doherty was examining one finger in a way that made me think he had been picking his nose.

“Right,” Byrne said, once he surfaced from his trance and registered that we were back. “We’ll be off, so. She’s all yours.”

Sometimes the local uniforms are pure diamond-reeling off details about everyone for miles around, listing half a dozen possible motives, handing you a prime suspect on a plate. Other times, all they want is to pass the hassle to you and get back to their game of Go Fish. This was obviously going to be other times.

“We’ll need you to hang on for a while,” Sam said, which I took as a good sign-the extent to which Frank had been running this show was making me edgy. “The Technical Bureau might want you to help with the search, and I’ll be asking you to give me all the local info you can.”

“She’s not local, sure,” Doherty said, wiping his finger on the side of his trousers. He was staring at me again. “Them up at Whitethorn House, they’re blow-ins. They’ve nothing to do with Glenskehy.”

“Lucky bastards,” Byrne mumbled, to his chest.

“She lived local, though,” Sam said patiently, “and she died local. That means we’ll be needing to canvass the area. You should probably give us a hand, seeing as ye know your way around.”

Byrne’s head sank farther into his shoulders. “They’re all mentallers, round here,” he said morosely. “Stone mentallers. That’s all you need to know.”

“Some of my best friends are mentallers,” Frank said cheerfully. “Think of it as a challenge.” He gave them a wave and headed off up the field, feet swishing wetly through the grass.

Sam and I followed him. Even without looking I could feel the worried little line between Sam’s eyebrows, but I didn’t have the energy to reassure him. Now I was out of that cottage, all I could feel was outrage, pure and simple. My face and my old name: it was like coming home one day and finding another girl coolly making dinner in your kitchen, wearing your comfiest jeans and singing along to your favorite CD. I was so furious I could barely breathe. I thought of that photo and I wanted to punch my smile straight off her face.

“Well,” I said, when we caught up with Frank at the top of the field, “that was fun. Can I go to work now?”

“DV must be a lot more entertaining than I thought,” Frank said, doing impressed, “if you’re in this much of a hurry. Sunglasses.”

I left the glasses where they were. “Unless this girl was a victim of domestic violence, and I’m not seeing anything that points that way, she’s got sweet fuck-all to do with me. So you dragged me out here why, exactly?”

“Hey, I’ve missed you, babe. Any excuse.” Frank grinned at me; I gave him a hairy look. “And you seriously figure she’s fuck-all to do with you? Let’s see you say that when we’re trying to ID her, and everyone you’ve ever known is freaking out and ringing up to give us your name.”

All the anger deflated out of me, leaving a nasty hollow at the bottom of my stomach. Frank, the little bollocks, was right. As soon as this girl’s face went into the papers alongside an appeal for her real name, there would be a tidal wave of people who had known me as Lexie, her as Lexie, me as me, all of them wanting to know who was dead and who both of us had been if we weren’t in fact Lexie Madison, and general hall-of-mirrors overload. Believe it or not, that was the first time it hit me: there was no way in the world for this to be as easy as Don’t know her, don’t want to know her, thanks for wasting my morning, see you around.