Sachs looked around and found the other device. She told Sommers this.

He explained exactly how to dismantle the cables and what to look for. Before she removed any evidence, though, Sachs laid the numbers and photographed the scene. Then she thanked Sommers and told him that was all she needed for now. They disconnected and she walked the grid, including the entrance and exit routes-which turned out to be in all likelihood a door nearby that led to the alley. It had a flimsy lock and had recently been jimmied open. She took pictures of this too.

She was about to go upstairs and join Pulaski when she paused.

Four victims here in the elevator.

Sam Vetter and four others dead at the hotel, a number in the hospital. Luis Martin.

And fear throughout the city, fear of this invisible killer.

In her imagination she heard Rhyme say, "You have to become him."

Sachs rested the evidence by the stairs and returned to the base of the elevator shaft.

I'm him, I'm Raymond Galt…

Sachs had trouble summoning the fanatic, the crusader, since that emotion didn't jibe, in her mind, with the extreme calculation that the man had shown so far. Anybody else would just have taken a shot at Andi Jessen or firebombed the Queens plant. But Galt was going to these precise, elaborate lengths to use a very complicated weapon to kill.

What did it mean?

I'm him…

I'm Galt.

Then her mind went still and up bubbled the answer: I don't care about motive. I don't care why I'm doing this. None of that matters. All that's important is to focus on technique, like focusing on making the most perfect splice or switch or connection I can to cause the most harm.

That's the center of my universe.

I've become addicted to the process, addicted to the juice…

And with that thought came another: It's all about angles. He had to get… I have to get the bus bar in just the right position to kiss the floor of the elevator car when it's near the lobby but not yet there.

Which means I have to watch the elevator in operation from all different perspectives down here to make sure the counterweight, the gears, the motor, the cables of the elevator don't knock aside the bus bar or otherwise interfere with the wire.

I have to study the shaft from all angles. I have to.

On her hands and knees Sachs made a circuit of the filthy basement all around the base of the shaft-anywhere that Galt could have seen the cable and bar and contacts. She found no footprints, no fingerprints. But she did find places where the ground had been recently disturbed, and it was not unreasonable to think that he'd crouched there to examine his deadly handiwork.

She took samples from ten locations and deposited them into separate evidence bags, marking them according to positions of the compass: "10' away, northwest." "7' away, south." She then gathered all the other evidence and climbed painfully on her arthritic legs to the lobby.

Joining Pulaski, Sachs looked into the interior of the elevator. It wasn't badly damaged. There were some smoke marks-accompanied by that terrible smell. She simply couldn't imagine what it would have been like to be riding in that car and suddenly have thirteen thousand volts race through your body. At least, she supposed, the vics would have felt nothing after the first few seconds.

She saw that he'd laid the numbers and taken pictures. "You find anything?"

"No. I searched the car too. But the panel hadn't been opened recently."

"He rigged everything from downstairs. And the bodies?"

His face was solemn, troubled, and she could tell that it had been a difficult chore. Still, he said evenly, "No trace. But there was something interesting. All three of them had wet soles. All their shoes."

"The fire department?"

"No, the fire was out by the time they got here."

Water. That was interesting. To improve the connection. But how did he get their shoes wet? Sachs then asked, "You said three bodies?"

"That's right."

"But that ESU guy said there were four vics."

"There were, but only three of them died. Here." He handed her a piece of paper.

"What's this?" On the slip was a name and phone number.

"The survivor. I figured you'd want to talk to her. Her name's Susan Stringer. She's at St. Vincent's. Smoke inhalation, some burns. But she'll be okay. They'll be releasing her in an hour or so."

Sachs was shaking her head. "I don't see how anybody could've survived. There were thirteen thousand volts in here."

Ron Pulaski replied, "Oh, she's disabled. In a wheelchair. Rubber tires, you know. Guess that insulated her."

"HOW'D HE DO?" Rhyme asked Sachs, who'd just returned to the lab.

"Ron? Little distracted. But he did a good job. Processed the bodies. That was tough. But he found something interesting. Somehow the vics all had wet shoes."

"How'd Galt manage that?"

"I don't know."

"You don't think Ron's too shaken up?"

"Not too. But some. But he's young. Happens."

"That's no excuse."

"No, it's not. It's an explanation."

"They're both the same to me," Rhyme muttered. "Where is he?"

The hour was after 8 p.m. "He went back to Galt's, thought he might've missed something."

Rhyme thought this wasn't a bad idea, though he was confident that the young officer had searched the scene well the first time. He added, "Just keep an eye on him. I won't risk anybody's life because he's distracted."

"Agreed."

The two of them and Cooper were here alone in the lab. McDaniel and the Kid were back at the federal building, meeting with Homeland Security, and Sellitto was down at the Big Building-One Police Plaza. Rhyme wasn't sure whom he was meeting with but there'd undoubtedly be a long list of people who wanted explanations about why there was no suspect in custody.

Cooper and Sachs were laying out the evidence that Sachs had collected at the office building. The tech then examined the cable and other items that were rigged at the base of the elevator shaft.

"There's one other thing." Sachs probably thought her voice was casual; in fact it was tripping with meaning to Rhyme. Tough to be in love with somebody; you can read them so well when they're up to something.

"What?" He gave her his inquisitor's gaze.

"There was a witness. She was in the elevator when the other people died."

"She hurt bad?"

"Apparently not. Smoke inhalation mostly."

"That would've been unpleasant. Burning hair." His nostrils flared slightly.

Sachs sniffed at her red strands. Her nose wrinkled too. "I'm taking a really long shower tonight."

"What'd she have to say?"

"I didn't get a chance to interview her… She's coming over here as soon as she's released."

"Here?" Rhyme asked with surprise. Not only was he skeptical of witnesses in the first place, but there was a security question about letting a stranger into the lab. If a terrorist cell was behind the attacks, they might want to sneak one of their members into the inner sanctum of the investigators.

But Sachs laughed, deducing his thoughts. "I checked her out, Rhyme. She's clean. No record, no warrants. Longtime editor of some furniture magazine. Besides, I thought it wasn't a bad idea-I wouldn't have to spend the time getting to and from the hospital. I can stay here and work the evidence."

"What else?"

She hesitated. Another smile. "I was explaining too much?"

"Uh-huh."

"Okay. She's disabled."

"Is she now? That's still not answering my question."

"She wants to meet you, Rhyme. You're a celebrity."

Rhyme sighed. "Fine."

Sachs turned to him, eyes narrowed. "You're not arguing."

Now he laughed. "Not in the mood. Let her come over. I'll interview her myself. Show you how it's done. Short and sweet."