Cooper shrugged. “Improbable coincidences do, as we know, happen. Fortunately, we are not purely dependent on the filling for identification.” He flicked through a neat stack of files on a long table and pulled out two transparencies, which he slapped up on a light board, one on top of the other. “There,” he said, and switched the light on.

And there was Rosie, illuminated and laughing against red brick and gray sky, with her chin up and her hair lifting in the wind. For a second she was all I could see. Then I saw the tiny white Xs dotting her face, and then I saw the empty skull staring out from behind it.

“As you can see from the points I have marked,” Cooper said, “the anatomical landmarks of the found skull—the size, angles and spacing of the eye sockets, nose, teeth, jaw, and so on—correspond precisely with Rose Daly’s features. While this does not constitute conclusive identification, it does constitute a reasonable degree of certainty, particularly when combined with the filling and with the circumstances. I have informed Detective Kennedy that he is at liberty to notify the family: I would have no difficulty in stating under oath that I believe this to be Rose Daly.”

I asked, “How did she die?”

“What you see, Detective Mackey,” Cooper said, sweeping an arm at the bones, “is what I have. In skeletonized remains, the cause of death can rarely be determined with certainty. She was clearly assaulted, but I have no way of positively eliminating, for example, the possibility that she suffered a fatal heart attack during the course of the assault.”

I said, “Detective Kennedy mentioned something about skull fractures.”

Cooper gave me a high-level snotty glare. “Unless I am gravely mistaken,” he said, “Detective Kennedy is not a qualified pathologist.”

I managed to grin at him. “He’s not a qualified bore, either, but he does the job just fine.”

The corner of Cooper’s mouth twitched. “Indeed,” he said. “Detective Kennedy is, albeit accidentally, correct that the skull has been fractured.”

He reached out one finger and rolled Rosie’s skull to the side. “There,” he said.

The thin white glove made his hand look wet and dead, sloughing away in layers. The back of Rosie’s head looked like a windscreen that had been bashed, more than once, with a golf club: it was thick with crazy spiderwebs of cracks radiating out in all directions, crisscrossing and ricocheting. Most of her hair had come away, it had been dumped beside her in a matted heap, but a few thin strands were still curling from the wrecked bone.