The Lucy commanded: Don't be so damn paranoid, soldier. Getting pretty tired of this. There're no IED's, no suicide bombers here, no bitter fog.

Get a grip.

One arm covering her breasts-there were apartments across the alley-she closed and locked the window. Looked down into the alley. Saw nothing.

It was then that somebody began pounding on the front door. Lucy spun around, gasping. She pulled on a bathrobe and hurried to the dark foyer. "Who's there?"

There was a pause, then a man's voice called, "I'm a police officer. Are you all right?"

She called, "What's wrong?"

"It's an emergency. Please open the door. Are you okay?"

Alarmed, she pulled the robe belt tight and undid the deadbolts, thinking of the bedroom window and wondering if somebody'd been trying to break it. She unhooked the chain.

Lucy twisted the lock, reflecting only after the door began to push open toward her that she probably should've asked to see an ID or a badge before she unhooked the chain. She'd been caught up in a very different world for so long that she'd forgotten there were still plenty of bad people stateside.

Amelia Sachs and Lon Sellitto arrived at the old apartment building in Greenwich Village, nestled on quaint Barrow Street.

"That's it?"

"Uh-huh," Sellitto said. His fingers were blue. His ears, red.

They looked into the alley beside the building. Sachs surveyed it carefully.

"What's her name?" she asked.

"Richter. Lucy I think's her first name."

"Which window's hers?"

"Third floor."

She glanced up at the fire escape.

They continued on to the front stairs of the apartment building. A crowd of people were watching. Sachs scanned their faces, still convinced that the Watchmaker had swept up at the first scene because he intended to return. Which meant he might have remained here too. But she saw no one that resembled him or his partner.

"We're sure it was the Watchmaker?" Sachs asked Frank Rettig and Nancy Simpson, cold and huddling next to the Crime Scene rapid response van, parked cockeyed in the middle of Barrow.

"Yep, he left one of those clocks," Rettig explained. "With the moon faces."

Sachs and Sellitto started up the stairs.

"One thing," Nancy Simpson said.

The detectives stopped and turned.

The officer nodded at the building, grimacing. "It won't be pretty."

Sachs and Sellitto ascended the stairs slowly. The air in the dim stairwell smelled of pine cleanser and oil furnace heat.

"How'd he get in?" Sachs mused.

"This guy's a ghost. He gets in however he fucking wants to."

She looked up the stairwell. They paused outside the door. A nameplate said, Richter/Dobbs.

It won't be pretty…

"Let's do it."

Sachs opened the door and walked into Lucy Richter's apartment.

Where they were met by a muscular young woman in sweats, hair pinned up. She turned away from the uniformed officer she'd been talking to. Her face darkened as she glanced at Sachs and Sellitto and noticed the gold badges around their necks.

"You're in charge?" asked Lucy Richter angrily, stepping forward, right in Lon Sellitto's face.

"I'm one of the detectives on the case." He identified himself. Sachs did too.

Lucy Richter put her hands on her hips. "What the hell do you people think you're doing?" the soldier barked. "You know there's some psycho leaving these goddamn clocks when he kills people. And you don't tell anybody? I didn't survive all these months of combat in the goddamn desert just to come home and get killed by some motherfucker because you don't bother to share that information with the public."

It took some time to calm her down.

"Ma'am," Sachs explained, "his M.O. isn't that he's delivering these clocks ahead of time to let people know he's on his way. He was here. In your apartment. You were lucky."

Lucy Richter was indeed fortunate.

About a half hour ago a passerby happened to see a man climb onto her fire escape and head for the roof. He'd called 911 to report it. The Watchmaker had apparently glanced down, realized he'd been spotted and fled.

A search of the neighborhood could find no trace of him and no witnesses had seen anyone matching the Watchmaker's image on the computer composite.

Sachs glanced toward Sellitto, who said, "We're very sorry for the incident, Ms. Richter."

"Sorry," she scoffed. "You need to go public with it."

The detectives glanced at each other. Sellitto nodded. "We will. I'll have Public Affairs make an announcement on the local news."

Sachs said, "I'd like to search your apartment for evidence he might've left. And ask you a few questions about what happened."

"In a minute. I have to make some calls. My family'll hear about this on the news. I don't want them to worry."

"This is pretty important," Sellitto said.

The soldier opened her cell phone. In a firm voice she added, "Like I said, in a minute."

"Rhyme, you there?"

"Go ahead, Sachs." The criminalist was in his laboratory, connected to Sachs via radio. He recalled that in the next month or so they'd planned to try a high-definition video camera mounted to her head or shoulder, broadcasting to Rhyme's lab, which would let him see everything that she saw. They'd joked and called it a James Bond toy. He felt a pang that it would not be Sachs inaugurating this device with him.

Then he forced the sentiment away. What he often told those working for him he now told himself: There's a perp out there; nothing matters but catching him and you can't do that if you're not concentrating 100 percent.

"We showed Lucy the composite of the Watchmaker. She didn't recognize him."

"How'd he get inside today?"

"Not sure. If he's sticking to his M.O. he picked the front door lock. But then I think he went up to the roof and climbed down the fire escape to the vic's window. He got inside, left the clock and was waiting for her. But for some reason he climbed back outside. That's when the wit outside saw him and the Watchmaker booked on out of here. Went back up the fire escape."

"Where was he inside her apartment?"

"He left the clock in the bathroom. The fire escape is off the master bedroom so he was in there too." She paused. Then came on a moment later. "They've been canvassing for witnesses but nobody saw him or his car. Maybe he and his partner are on foot since we've got his SUV." A half dozen different subway lines serve Greenwich Village and they could easily have escaped via any of them.

"I don't think so." Rhyme explained that he felt the Watchmaker and his assistant would prefer wheels. The choice of using vehicles or not when committing a crime is a consistent pattern in a criminal's M.O. It rarely changes.

Sachs searched the bedroom, the fire escape, the bathroom and the routes he would've taken to get to those places. She checked the roof too. It had not been recently tarred, she reported.

"Nothing, Rhyme. It's like he's wearing a Tyvek suit of his own. He's just not leaving anything behind."

Edmond Locard, the famed French criminalist, developed what he called the exchange principle, which stated that whenever a physical crime occurs, there is some transfer of evidence between the criminal and the location. He leaves something of himself at the scene and he takes some of the scene with him when he departs. The principle is deceptively optimistic, though, because sometimes the trace is so minuscule it's missed and sometimes it's easily located but provides no helpful leads for investigators. Still Locard's principle holds that there would be some transfer of materials.