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."