“Or maybe none of the above,” Frank said. “We already know our girl wasn’t above telling a few little white ones.”

Sam nodded. “In September, Daniel inherited Whitethorn House near Glenskehy from his great-uncle, Simon March, and they all moved in. Last Wednesday night, the five of them were home, playing poker. Lexie got knocked out first and went for a walk around half past eleven-late-night walks were a regular part of her routine, the area’s safe, the rain hadn’t started in yet, the others didn’t think twice. They finished up a little after midnight and went to bed. They all describe the card game the same way, who won how much on what hand-little differences here and there, but that’s only natural. We’ve interviewed all of them several times, and they haven’t budged an inch. Either they’re innocent or they’re dead organized.”

“And the next morning,” Frank said, finishing off the timeline with a flourish, “she shows up dead.”

Sam pulled a handful of papers out of the pile on his desk, went to the whiteboard and stuck something in one corner: a surveyor’s map of a patch of countryside, detailed down to the last house and boundary fence, marked with neat Xs and squiggles in colored highlighter. “Here’s Glenskehy village. Whitethorn House is just under a mile to the south. Here, about halfway in between and a little to the east, that’s the derelict cottage where we found our girl. I’ve marked all the obvious routes she might have taken to get there. The Bureau and the uniforms are still searching them: nothing yet. According to her mates, she always went out the back gate for her walk, wandered around the little lanes for an hour or so-it’s a maze of them, all around there-and came home either by the front or by the back, depending on what route took her fancy.”

“In the middle of the night?” O’Kelly wanted to know. “Was she mental, or what?”

“She always took the torch we found on her,” Sam said, “unless the night was bright enough to see without. She was mad for the old walks, went out almost every night; even if it was lashing rain, she mostly just bundled up warm and went anyway. I wouldn’t say it’s exercise she was after, more privacy-living that close with the other four, it’s the only time she got to herself. They don’t know whether she ever went to the cottage, but they did say she liked it. Just after they first moved in, the five of them spent a day wandering all round Glenskehy, getting the lie of the land. When they spotted the cottage, Lexie wouldn’t move on till she’d gone in and had a look around, even though the others told her the farmer would probably be out with his shotgun any minute. She liked that it had been left there, even though no one was using it-Daniel said she ‘likes inefficiency,’ whatever that means. So we can’t rule out the possibility that it was a regular stop on her walks.”

Definitely not Irish, then, or at least not brought up here. Famine cottages are all over the countryside, we barely even see them any more. It’s only tourists-and mostly tourists from newer countries, America, Australia -who look at them long enough to feel their weight.

Sam found another piece of paper to add to the whiteboard: a floor plan of the cottage, with a neat, tiny scale at the bottom. “However she ended up there,” he said, pressing the last corner into place, “that’s where she died-against this wall, in what we’re calling the outer room. Sometime after death and before rigor set in, she was moved to the inner room. That’s where she was found, early Thursday morning.”

He gestured to Cooper.

Cooper had been gazing into space, in a lofty trance. He took his time: cleared his throat primly, glanced around to make sure he had everyone’s full attention. “The victim,” he said, “was a healthy white female, five feet five inches in height, a hundred and twenty pounds. No scars, tattoos or other identifying marks. She had a blood alcohol content of.03, consistent with drinking two to three glasses of wine a few hours previously. The toxicology screen was otherwise clear-at the time of death she had consumed no drugs, toxins or medications. All organs were within normal limits; I found no defects or signs of disease. The epiphyses of the long bones are completely fused and the inner sutures of the skull bones show early signs of fusion, placing her age around the late twenties. It is clear from the pelvis that she has never delivered a child.” He reached for his water glass and took a judicious sip, but I knew he wasn’t finished; the pause was for effect. Cooper had something up his sleeve.

He put down the glass, aligning it neatly in the corner of the desk. “She was, however,” he said, “in the early stages of pregnancy.” He sat back and watched the impact.

“Ah, Jesus,” Sam said softly. Frank leaned back against the wall and whistled, one long low note. O’Kelly rolled his eyes.

That was all this case needed. I wished I had had the sense to sit down. “Any of her mates mention this?” I asked.

“Not a one,” Frank said, and Sam shook his head. “Our girl kept her friends close and her secrets closer.”

“She might not even have known,” I said. “If her cycle wasn’t regular-”

"Ah, Jaysus, Maddox,” said O’Kelly, horrified. “We don’t want to hear about that carry-on. Put it in a report or something.”

"Any chance of IDing the father through DNA?” Sam asked.

“I see no reason why not,” Cooper said, “given a sample from the putative father. The embryo was approximately four weeks old and just under half a centimeter long, and was-”

"Christ,” said O’Kelly; Cooper smirked. “Skip the bloody details and get on with it. How’d she die?”

Cooper left a loud pause, to show everyone that he wasn’t taking orders from O’Kelly. “At some point on Wednesday night,” he said, when he figured his point was made, “she suffered a single stab wound to the right chest. The probability is that the attack came from the front: the angle and point of entry would be difficult to achieve from behind the victim. I found slight abrasions to both palms and one knee, consistent with a fall on hard ground, but no defensive wounds. The weapon was a blade at least three inches long, with a single edge, a sharp point and no distinctive features-it could have been any large pocketknife, even a sharp kitchen knife. This blade entered on the midclavicular line at the level of the eighth rib, at an upward angle, and nicked the lung, leading to a tension pneumothorax. To put it as simply as possible”-he threw O’Kelly a snide sidelong glance-“the blade created a flap valve in the lung. Each time she inhaled, air escaped from the lung into the pleural space; when she exhaled, the flap closed, leaving the air trapped. Prompt medical attention could almost certainly have saved her. In the absence of such attention, however, the air gradually accumulated, compressing the other thoracic organs within the chest cavity. Eventually the heart was no longer able to fill with blood, and she died.”

There was a tiny silence, only the soft hum of the fluorescents. I thought of her in that cold ruined house, with night birds keening above her and rain gentle all around, dying of breathing.

“How long would that have taken?” Frank asked.

“The progression would depend on a variety of factors,” Cooper said. “If, for example, the victim ran for any distance after being stabbed, her breathing would have accelerated and deepened, hastening the development of the tension pneumothorax. The blade also left a minute nick in one of the major veins of the chest; with activity, this nick grew into a tear, and she would gradually have begun to bleed quite heavily. To give a tentative estimate, I would guess that she became unconscious approximately twenty to thirty minutes after receiving the injury, and died perhaps ten or fifteen minutes later.”

“In that half hour,” Sam asked, “how far could she have got?”