In addition, my years of work on these cases often added another experienced perspective to that of the police team-and sometimes it resulted in recalling a distinctive detail or trait that would lead the investigators to a repeat offender in this category of crimes in which the recidivist rate was so extraordinarily high.

Mercer started the engine and turned up the heat in the old department Crown Vic that had responded to more sexual assaults than most officers ever would in a lifetime. "So, did anything there speak to you?" Mercer said, smiling at me.

I rubbed my gloved hands together against the harsh winter chill that had seeped through the cracks around the car windows. Lots of veteran cops got vibes at crime scenes, claiming to be able to figure out something about the assailant by being in the same space. I shook my head. "Nothing you don't already know. Yet one more sick puppy who was somehow aroused by forcing a woman he'd never seen before to engage in a sexual act."

"There are buildings with doormen on both corners of the block. This is a fully occupied brownstone on a well-lighted street. He's a cool case, this guy. He got her at the front door on top of the stoop, as she was unlocking it-"

"She told you that?"

Mercer had been waiting at the hospital when the young woman emerged from the anesthetic late last evening. "Too many tubes coming out of the kid to speak, and the docs only gave me fifteen minutes with her. I asked some basics until she ran out of steam. She squeezed my hand like I told her for some yes-and-no kind of questions."

We were driving to the hospital, just a few blocks away on York Avenue at Sixty-eighth Street. Mercer stopped in to check on his victim on the way to his office this morning, and insisted on seeing her again, as he would every day until she recovered. He wanted to tell the young exchange student that he had telephoned her parents, in Sweden, and that they were flying here tomorrow. Until they arrived, he would be the closest thing to family she would have at her side.

"Did Annika know he had the knife when he accosted her?"

"She never even heard him coming. I figure the first thing she felt was his arm yoking her neck and the blade of the knife scratching the side of her throat."

"Not a particularly distinctive MO," I said.

"You looking for creative, too, Alex?"

I shook my head.

"It's all in the details, as you know. Exactly what words he said, how he touched her, what he smelled like. It may be a couple of days until we can get all that from her."

"And hope in the meantime that he doesn't feel it necessary to finish the job with another victim tonight or tomorrow."

Mercer flashed his badge at the security guard in front of the hospital driveway, who motioned him to leave the car right at the curb.

Sophisticated monitors beeped their familiar noises as we pushed open the doors into the surgical ICU. Nurses were engaged in every one of the eight cubicles, tending to patients in the most critical phase of care.

Mercer walked to the glass-enclosed area where Annika Jelt lay in bed.

"She's awake, Detective. You can come in," the nurse said.

I remained in the doorway as Mercer took a step to the bedside. He reached out his large hand and placed it on Annika's arm, above the intravenous needle that carried fluids back into her slim body. As she felt his touch, the young woman turned her head toward us and tried to smile, recognizing her new friend and protector.

"Hello," she whispered, barely able to move her mouth because of the tubes coming out of her nostrils.

Mercer leaned his six-foot-six-inch frame over the bed railing and gently stroked Annika's forehead. "Don't try to talk. I just came back to check on you. Make sure they're treating you right."

The nurse walked to the far side of the bed and adjusted the pillows behind her head. "Detective Wallace told me he'd haul me off to the clink if we don't get you up and out of here as soon as possible."

She twisted her head back toward the nurse and forced another smile.

"I spoke with your mother, Annika. It's okay. She and your dad will be here tomorrow."

At the mention of her parents, the girl's eyes filled with tears and a guttural cry escaped from her mouth. She wanted to speak but couldn't find the strength, or the right words.

"They know you're going to be fine. They want to come over here and be with you."

I couldn't understand what she was mumbling. Her head was moving back and forth, causing all the monitors to go into high gear. It was something about what she wanted.

"I know you want to go home," Mercer said. Her hand was clasped in his and he continued to try to calm her by stroking her hair.

I bit my lip and thought of how isolated and frightened she must be. Alone in a foreign country, victim of a crime that almost took her life, and not even able to speak on the telephone to assure her family that she would survive.

"Remember the lady I told you about, my friend Alex? I've brought her here to meet you," Mercer said, stepping back from the bed that was surrounded with medical equipment so that Annika could see me.

I came in closer and she dropped his hand, gesturing toward mine. I took his place by her side, covering her cold fingers with my own, and let Mercer finish speaking. "Alex and I are going to find this man, Annika. All you have to do is get strong again. That's your only assignment."

"Mercer's right. You need to get all the rest you can. We'll be back to see you every day. We'll get you everything you need."

"Home?" This time I could hear her clearly.

"Of course you can go home as soon as you're well enough to travel," I said.

"She's almost due for her pain medication," the nurse said. "She gets agitated whenever anyone mentions her family. She doesn't want them to see her this way and she worries about how upset they must be. They never wanted her to come to New York for school."

We waited until she had composed herself, and the MorphiDex that the nurse added to the drip began to take effect.

Annika's watery brown eyes blinked repeatedly, like she was fighting sleep, determined to make sure that Mercer stayed by her side. She closed them at last, her small head barely making a dent in the firm pillows behind her, looking pale and sallow against the crisp white hospital linens. The lifesaving machinery that surrounded her outweighed her twofold. Its blinking lights and beeping noises wouldn't disturb her medicated slumber, and I hoped as well that nightmare visions of her attacker couldn't penetrate the veil drawn around her by the strong painkillers.

It was not even five o'clock when we got back into the car for the ride downtown to my office, but it was already pitch-black and the windchill factor had dropped several notches.

Mercer's cell phone vibrated and he unhitched it from his belt to flip it open as he pulled out of the driveway onto York Avenue.

"Sure, Bob. I'll take a preliminary," he said, looking over at me.

It was Bob Thaler, the chief serologist at the medical examiner's office, who had worked up a quick analysis, less than twenty-four hours after getting the evidence found at the scene of Annika's assault. These tentative findings would later be validated with further testing. This first run wouldn't hold up in court, but it would give us an immediate idea if there was evidence of value.

"Yeah, we picked up those four cigarette butts from the stoop in front of the building. You find something?"

Thaler gave him an answer, which caused Mercer to turn and wink at me. Good news, I assumed.

But their conversation went on, and as he listened, Mercer's smile faded to a serious expression, almost an angry one. He hung up the phone, dropped it on the seat between us, and accelerated onto the FDR Drive.