“I agree,” Stavely said. He was examining her arms and hands. “Her right hand is larger than the left. The arm is heavier.”

Blake was leaning over, looking at the damaged face. “So?”

“I think they’re self-inflicted,” Stavely said.

“Are you sure?”

Stavely was circling the head of the table, looking for the best light. The wounds were swelled by the paint, raw and open. Green, where they should have been red.

“I can’t be sure,” he said. “You know that. But probability suggests it. If the guy did them, what are the chances he would have put them in the only place she could have put them herself?”

“He made her do it,” Reacher said.

“How?” Blake asked.

“I don’t know how. But he makes them do a hell of a lot. I think he makes them put the paint in the tub themselves.”

“Why?”

“The screwdriver. It’s to get the lids off with. The scratches were an afterthought. If he’d been thinking about the scratches, he’d have made her get a knife from the kitchen instead of the screwdriver. Or as well as the screwdriver.”

Blake stared at the wall. “Where are the cans right now?”

“Materials Analysis,” Poulton said. “Right here. They’re examining them.”

“So take the screwdriver over there. See if there are any marks that match.”

The technician put the screwdriver in a clear plastic evidence bag and Poulton shrugged off his gown and kicked off his overshoes and hurried out of the room.

“But why?” Blake said. “Why make her scratch herself like that?”

“Anger?” Reacher said. “Punishment? Humiliation? I always wondered why he wasn’t more violent.”

“These wounds are very shallow,” Stavely said. “I guess they bled a little, but they didn’t hurt much. The depth is absolutely consistent, all the way down each of them. So she wasn’t flinching.”

“Maybe ritual,” Blake said. “Symbolic, somehow. Four parallel lines mean anything?”

Reacher shook his head. “Not to me.”

“How did he kill her?” Blake asked. “That’s what we need to know.”

“Maybe he stabbed her with the screwdriver,” Harper said.

“No sign of it,” Stavely said. “No puncture wounds visible anyplace that would kill a person.”

He had the final section of the body bag peeled back and was washing paint away from her midsection, probing with his gloved fingers under the acetone jet. The technician lifted the rubber square away and then she lay naked under the lights, collapsed and limp and utterly lifeless. Reacher stared at her and remembered the bright vivacious woman who had smiled with her eyes and radiated energy like a tiny sun.

“Is it possible you can kill somebody and a pathologist can’t tell how?” he asked.

Stavely shook his head.

“Not this pathologist,” he said.

He shut off the acetone stream and let the hose retract into its reel on the ceiling. Stepped back and turned the ventilation fan back to normal. The room turned quiet again. The body lay on the table, as clean as it was ever going to get. The pores and folds of skin were stained green and the skin itself was lumpy and white like something that lives at the bottom of the sea. The hair was spiky with residue, roughly hacked around the scalp, framing the dead face.

“Fundamentally two ways to kill a person,” Stavely said. “Either you stop the heart, or you stop the flow of oxygen to the brain. But to do either thing without leaving a mark is a hell of a trick.”

“How would you stop the heart?” Blake asked.

“Short of firing a bullet through it?” Stavely said. “Air embolism would be the best way. A big bubble of air, injected straight into the bloodstream. Blood circulates surprisingly fast, and an air bubble hits the inside of the heart like a stone, like a tiny internal bullet. The shock is usually fatal. That’s why nurses hold up the hypodermic and squirt a little liquid out and flick it with their nail. To be sure there’s no air in the mix.”

“You’d see the hypodermic hole, right?”

“Maybe, maybe not. And definitely not on a corpse like this. The skin is ruined by the paint. But you’d see the internal damage to the heart. I’ll check, of course, when I open her up, but I’m not optimistic. They didn’t find anything like that on the other three. And we’re assuming a consistent MO here, right?”

Blake nodded. “What about oxygen to the brain?”

“Suffocation, in layman’s terms,” Stavely said. “It can be done without leaving much evidence. Classic thing would be an old person, wasted and weak, gets a pillow held over the face. Pretty much impossible to prove. But this isn’t an old person. She’s young and strong.”

Reacher nodded. He had suffocated a man once, way back in his long and checkered career. He had needed all of his considerable strength to hold the guy’s face down on a mattress, while he bucked and thrashed and died.

“She’d have fought like crazy,” he said.

“Yes, I think she would,” Stavely said. “And look at her. Look at her musculature. She wouldn’t have been a pushover.”

Reacher looked away instead. The room was silent and cold. The awful green paint was everywhere.

“I think she was alive,” he said. “When she went in the tub.”

“Reasoning?” Stavely asked.

“There was no mess,” Reacher said. “None at all. The bathroom was immaculate. What was she, one twenty? One twenty-five? Hell of a dead weight to heave into the tub without making some kind of a mess.”

“Maybe he put the paint in afterward,” Blake said. “On top of her.”

Reacher shook his head. “It would have floated her up, surely. It looks like she slipped right in there, like you get into a bath. You know, you point your toe, you get under the water.”

“We’d need to experiment,” Stavely said. “But I think I agree she died in the tub. The first three, there was no evidence they were touched at all. No bruising, no abrasions, no nothing. No postmortem damage either. Moving a corpse usually damages the ligaments in the joints, because there’s no muscle tension there to protect them. At this point, my guess is they did whatever they did strictly under their own power.”

“Except kill themselves,” Harper said.

Stavely nodded. “Suicide in bathtubs is pretty much limited to drowning while drunk or drugged, or opening your veins into warm water. Obviously, this isn’t suicide.”

“And they weren’t drowned,” Blake said.

Stavely nodded again. “The first three weren’t. No fluid of any kind in the lungs. We’ll know about this one soon as she’s opened up, but I would bet against it.”

“So how the hell did he do it?” Blake said.

Stavely stared down at the body, something like compassion in his face.

“Right now, I have no idea,” he said. “Give me a couple of hours, maybe three, I might find something.”

“No idea at all?”

“Well, I had a theory,” Stavely said. “Based on what I read about the other three. Problem is, now I think the theory is absurd.”

“What theory?”

Stavely shook his head. “Later, OK? And you need to leave now. I’m going to cut her up, and I don’t want you here for that. She needs privacy, time like this.”