"I CUTA few corners," Stavely said. "You need to understand that, OK? You guys are in a big hurry, and we think we're dealing with a consistent MO, so all I did was look at the questions that the first three left behind. I mean, we all know what it isn't, right?"

"It isn't everything, far as we know," Blake said.

"Right. No blunt trauma, no gunshots, no stab wounds, no poison, no strangulation."

"So what is it?"

Stavely moved a complete circle around the table and sat down at an empty chair, on his own, three seats from Poulton and two from Reacher.

"Did she drown?" Poulton asked.

Stavely shook his head. "No, just like the first three didn't. I took a look at her lungs, and they were completely clear."

"So what is it?" Blake asked again.

"Like I told you," Stavely said. "You stop the heart, or you deny oxygen to the brain. So first, I looked at her heart. And her heart was perfect. Completely undamaged. Same as the other three. And these were fit women. Great hearts. It's easier to spot the damage on a good heart. An older person might have a bad heart, with preexisting damage, you know, furring or scarring from previous cardiac trouble, and that can hide new damage. But these were perfect hearts, like athletes. Any trauma, it would have stuck out a mile. But there wasn't any. So he didn't stop their hearts."

"So?" Blake asked.

"So he denied them oxygen," Stavely said. "It's the only remaining possibility."

"How?"

"Well, that's the big question, isn't it? Theoretically he could have sealed off the bathroom and pumped the oxygen out and replaced it with some inert gas."

Blake shook his head. "That's absurd."

"Of course it is," Stavely said. "He'd have needed equipment, pumps, tanks of gas. And we'd have found residue in the tissues. Certainly in the lungs. There aren't any gases we wouldn't have detected."

"So?"

"So he choked off their airways. It's the only possibility. "

"You said there are no signs of strangulation."

Stavely nodded. "There aren't. That's what got me interested. Strangulation normally leaves massive trauma to the neck. All kinds of bruising, internal bleeding. It sticks out a mile. Same for garroting."

"But?"

"There's something called gentle strangulation."

"Gentle?" Harper said. "Awful phrase."

"What is it?" Poulton asked.

"A guy with a big arm," Stavely said. "Or a padded coat sleeve. Gentle consistent pressure, that will do it."

"So is that it?" Blake asked.

Stavely shook his head. "No, it isn't. No external marks, but to get far enough to kill them, you leave internal damage. The hyoid bone would be broken, for instance. Certainly cracked, at least. Other ligament damage too. It's a very fragile area. The voice box is there."

"And you're going to tell me there was no damage, I guess," Blake said.

"Nothing gross," Stavely said. "Did she have a cold, when you met with her?"

He looked at Harper, but Reacher answered.

"No," he said.

"Sore throat?"

"No."

"Husky voice?"

"She seemed pretty healthy to me."

Stavely nodded. Looked pleased. "There was some very, very slight swelling inside the throat. It's what you'd get recovering from a head cold. Mucus drip might do it, or a very mild strep virus. Ninety-nine times in a hundred, I'd ignore it completely. But the other three had it too. That's a little coincidental for me."

"So what does it mean?" Blake asked.

"It means he pushed something down their throats," Stavely said.

Silence in the room.

"Down their throats?" Blake repeated.

Stavely nodded. "That was my guess. Something soft, something which would slip down and then expand a little. Maybe a sponge. Were there sponges in the bathrooms?"

"I didn't see one in Spokane," Reacher said.

Poulton was back in the piles of paper. "Nothing on the inventories."

"Maybe he removed them," Harper said. "He took their clothes."

"Bathrooms without sponges," Blake said slowly. "Like the dog that didn't bark."

"No," Reacher said. "There wasn't a sponge before, is what I meant."

"You sure?" Blake asked.

Reacher nodded. "Totally."

"Maybe he brings one with him," Harper said. "The type he prefers."

Blake looked away, back to Stavely. "So that's how he's doing it? Sponges down their throats?"

Stavely stared at his big red hands, resting on the tabletop.

"It has to be," he said. "Sponges, or something similar. Like Sherlock Holmes, right? First you eliminate the impossible, and whatever you're left with, however improbable, has got to be the answer. So the guy is choking them to death by pushing something soft down their throats. Something soft enough not to cause blunt trauma internally, but something dense enough to block the air."

Blake nodded, slowly. "OK, so now we know."

Stavely shook his head. "Well, no, we don't. Because it's impossible."

"Why?"

Stavely just shrugged miserably.

"Come here, Harper," Reacher said.

She looked at him, surprised. Then she smiled briefly and stood up and scraped her chair back and walked toward him.

"Show, don't tell, right?" she said.

"Lie on the table, OK?" he asked.

She smiled again and sat on the edge of the table and swiveled into position. Reacher pulled Poulton's pile of paper over and pushed it under her head.

"Comfortable?" he asked.

She nodded and fanned her hair and lay back like she was at the dentist. Pulled her jacket closed over her shirt.

"OK," Reacher said. "She's Alison Lamarr in the tub."

He pulled the top sheet of paper out from under her head and glanced at it. It was the inventory from Caroline Cooke's bathroom. He crumpled it into a ball.

"This is a sponge," he said. Then he glanced at Blake. "Not that there was one in the room."

"He brought it with him," Blake said.

"Waste of time if he did," Reacher said. "Because watch."

He put the crumpled paper to Harper's lips. She clamped them tight.

"How do I get her to open her mouth?" he asked. "In the full and certain knowledge that what I'm doing is going to kill her?"

He leaned close and used his left hand under her chin, his fingers and thumb up on her cheeks. "I could squeeze, I guess. Or I could clamp her nose until she had to breathe. But what would she do?"

"This," Harper said, and threw a playful roundhouse right which caught Reacher high on the temple.

"Exactly," he said. "Two seconds from now, we're fighting, and there's a gallon of paint on the floor. Another gallon all over me. To get anywhere with this, I'd have to get right in the tub with her, behind her or on top of her."

"He's right," Stavely said. "It's just impossible. They'd be fighting for their lives. No way to force something into somebody's mouth against their will, without leaving bruises on their cheeks, their jaws, all over them. Flesh would tear against their teeth, their lips would be bruised and cut, maybe the teeth themselves would loosen. And they'd be biting and scratching and kicking. Traces under their nails. Bruised knuckles. Defensive injuries. It would be a fight to the death, right? And there's no evidence of fighting. None at all."

"Maybe he drugged them," Blake said. "Made them passive, you know, like that date-rape thing."

Stavely shook his head.

"Nobody was drugged," he said. "Toxicology is absolutely clear, all four cases."

The room went silent again and Reacher pulled Harper upright by the hands. She slid off the table and dusted herself down. Walked back to her seat.

"So you've got no conclusions?" Blake asked.

Stavely shrugged. "Like I said, I've got a great conclusion. But it's an impossible conclusion."

Silence.

"I told you, this is a very smart guy," Reacher said. "Too smart for you. Way too smart. Four homicides, and you still don't know how he's doing it."

"So what's the answer, smart guy?" Blake said. "You going to tell us something four of the nation's best pathologists can't tell us?"

Reacher said nothing.

"What's the answer?" Blake asked again.

"I don't know," Reacher said.

"Great. You don't know."

"But I'll find out."

"Yeah, like how?"

"Easy. I'll go find the guy, and I'll ask him."

FORTY-ONE MILES AWAY, slightly east of north, the colonel was two miles from his office, after a ten-mile journey. He had taken the shuttle bus from the Pentagon's parking lot and gotten off near the Capitol. Then he had hailed a cab and headed back over the river to the National Airport's main terminal. His uniform was in a leather one-suiter slung on his shoulder, and he was cruising the ticket counters at the busiest time of day, completely anonymous in a teeming crush of people.

"I want Portland, Oregon," he said. "Open roundtrip, coach."

A clerk entered the code for Portland and his computer told him he had plenty of availability on the next nonstop.

"Leaves in two hours," he said.

"OK," the colonel said.

"YOU THINK YOU'LL find the guy?" Blake repeated.

Reacher nodded. "I'll have to, won't I? It's the only way."

There was silence in the conference room for a moment. Then Stavely stood up.

"Well, good luck to you, sir," he said.

He walked out of the room and closed the door softly behind him.

"You won't find the guy," Poulton said. "Because you're wrong about Caroline Cooke. She never served in ordnance warehousing or weapons testing. She proves your theory is shit."

Reacher smiled. "Do I know all about FBI procedures? "

"No, you don't."

"So don't talk to me about the Army. Cooke was an officer candidate. Fast-track type. Had to be, to finish up in War Plans. People like that, they send them all over the place first, getting an overview. That summary you've got in your file is incomplete."

"It is?"

Reacher nodded. "Has to be. If they listed everywhere she was posted, you'd have ten pages before she made first lieutenant. You check back with Defense, get the details, you'll find she was someplace that could tie her in."

The silence came back. There was a faint rush from the forced-air heating and a buzz from a failing fluorescent tube. A high-pitched whistle from the silent television. That was all. Nothing else. Poulton stared at Blake. Harper stared at Reacher. Blake looked down at his fingers, which were tapping on the table with silent fleshy impacts.

"Can you find him?" he asked.

"Somebody's got to," Reacher said. "You guys aren't getting anywhere."

"You'll need resources."

Reacher nodded. "A little help would be nice."

"So I'm gambling here."

"Better than putting all your chips behind a loser."

"I'm gambling big-time. With a lot at stake."

"Like your career?"

"Seven women, not my career."

"Seven women and your career."

Blake nodded, vaguely. "What are the odds?"

Reacher shrugged. "With three weeks to do it in? It's a certainty."

"You're an arrogant bastard, you know that?"

"No, I'm realistic, is all."

"So what do you need?"

"Remuneration," Reacher said.

"You want to get paid?"

"Sure I do. You're getting paid, right? I do all the work, only fair I get something out of it too."

Blake nodded. "You find the guy, I'll speak to Deerfield up in New York, get the Petrosian thing forgotten about."

"Plus a fee."

"How much?"

"Whatever you think is appropriate."

Blake nodded again. "I'll think about it. And Harper goes with you, because right now the Petrosian thing ain't forgotten about."

"OK. I can live with that. If she can."

"She doesn't get a choice," Blake said. "What else?"

"Set me up with Cozo. I'll start in New York. I'll need information from him."

Blake nodded. "I'll call him. You can see him tonight. "

Reacher shook his head. "Tomorrow morning. Tonight, I'm going to see Jodie."