Lash slumped back in his chair and let the senior evaluator’s report fall from his hands. The tests he’d fought so hard to get brought him no closer to an answer.

There was a knock at his door, and he looked up to see Tara Stapleton leaning in, her long, intent face framed by thick auburn hair.

“Lunch?” she asked.

Lash gathered Lewis Thorpe’s papers together and stuffed them back into the folder. “Sure.”

Already, the cafeteria down the hall felt like an old friend. It was bright and almost festive, and more crowded now than it had been on his two earlier visits. He fell in line at the buffet rail, helped himself to another espresso and a sandwich, then followed Tara to an empty table near the rear wall. She’d taken only a cup of soup and some tea, and as Lash watched she tore open a packet of artificial sweetener and poured it into the cup. Her reserved, preoccupied silence remained. But right now, that seemed all right: he wasn’t eager to field a lot of questions about how his investigation was going.

“How long have you worked at Eden?” he asked after a moment.

“Three years. Since just after its founding.”

“And it’s as great a place to work as Mauchly says?”

“It always has been.”

Lash waited as she stirred her soup, a little uncertain what she meant by this. “Tell me about Silver.”

“How do you mean.”

“Well, what’s he like? He wasn’t at all what I expected.”

“Me, neither.”

“I take it this was the first time you’ve met him face to face.”

“I saw him once before, at the first anniversary celebration. He’s a very private person. Never leaves his penthouse, as far as anybody knows. Communicates by cell or videophone. It’s just him up there. Him and Liza.”

Liza. Silver had mentioned that name, too. At the time, Lash had thought it a slip of the tongue. “Liza?”

“The computer. His life’s work. What makes Eden possible. Liza’s his one true love. Kind of ironic, really, given the nature of our business. He does most of his communicating to the board and the staff through Mauchly.”

Lash was surprised. “Really?”

“Mauchly’s his right-hand man.”

Lash noticed that somebody was looking at him from across the cafeteria. The youthful face, the bright thatch of hair, seemed familiar. Then he realized who it was: Peter Hapwood, the evaluation engineer Mauchly had introduced him to the day of the class reunions. Hapwood smiled, waved. Lash waved back.

He returned his attention to Tara, who was once again stirring her soup. “Tell me more about Liza,” he said.

“It’s a hybrid supercomputer. Nothing else like it in the world.”

“Why?”

“It’s the only large computer built entirely around a core of artificial intelligence.”

“And how did Silver come to build it?”

Tara took a sip of tea. “You hear rumors. Stories, really. I don’t know exactly how true any of them are. Some people say Silver had a lonely, traumatic childhood. Others say he was coddled, doing differential equations at the age of eight. He’s never talked about it on record. All anybody knows for sure is, by the time he got to college, he was doing pioneering work in AI. Brilliant, genius-level stuff. His graduate work centered around a computer that could learn for itself. He gave it a personality, made its problem-solving algorithms more and more sophisticated. Eventually, he proved a computer that can teach itself could solve problems far more difficult than any hand-coded computer. Later, to finance further research, he farmed out Liza’s processing cycles to places like the Jet Propulsion Laboratory, the Human Genome Project.”

“And then he had his brainstorm. Eden, with Liza as the computational core. And the rest, as they say, is history.” Lash took a sip of coffee. “So what’s Liza like to work with?”

There was a pause. “We never get near the core routines or intelligence. Liza’s physical plant is in the penthouse, and only Silver has access. Everybody else — scientists, technicians, even the computer programmers — uses the corporate computer grid and Liza’s data abstraction layer.”

“Liza’s what?”

“A shell that creates virtual machines within the computer’s memory space.” Tara paused again. More and more pauses were creeping into her sentences. Then, abruptly, she stood up.

“I’m sorry,” she said. “Could we talk about this some other time? I have to go.”

And without another word she turned and left the cafeteria.

When Mauchly walked into the office around four, Lash was standing before his whiteboard. The man moved so silently Lash didn’t notice him until he was by his side.

“Christ!” Lash jumped, dropping his marker.

“Sorry. Should have knocked.” Mauchly glanced at the bulletin board. “Race, age, type, personality, employment, geographics, victims. What’s this?”

“I’m trying to type the killer. Assemble a profile.”

Mauchly turned his placid gaze on Lash. “We still don’t know there’s a killer.”

“I’ve gone over all your records. There’s nothing psychologically wrong with the Thorpes or the Wilners, zero clinical evidence of suicide. It would be a waste of time to explore that avenue further. And you heard what Lelyveld said in the boardroom: we don’t have time.”

“But there’s no signs of murder, either. The Thorpes’ security camera, for one thing. It didn’t show anybody entering or leaving the house.”

“It’s a lot easier to cover up a murder than to cover up a suicide. Security cameras can be interfered with. Alarms can be bypassed.”

Mauchly thought about this. Then he looked back at the writing on the board. “How do you know the killer is in his late twenties or early thirties?”

“I don’t. That’s the baseline for serial killers. We have to start with the pattern, and refine from there.”

“And how about this: that he’s either well employed or has access to money?”

“He killed people on opposite coasts within a week of each other. That’s not the modus operandi of a drifter or a hitchhiker: their killing patterns chart erratically across short distances.”

“I see. And this?” Mauchly pointed to the scrawled words, TYPE: UNKNOWN.

“That’s the troubling part. Usually, we type serial killers as organized or disorganized. Organized killers control their crime scenes and their victims. They’re smart, socially acceptable, sexually competent. They target strangers, hide their corpses. On the other hand, disorganized killers know their victims, act suddenly and spontaneously, feel little or no stress during the crime, have few work skills, leave the victim at the scene of the crime.”

“And?”

“Well, if someone murdered the Thorpes and the Wilners, he exhibits traits of both the organized and disorganized killer. There’s no coincidence here: he’d have to know the victims. Yet he left them at the scene, like a disorganized killer. But again, the scene isn’t in the least bit sloppy. Such inconsistencies are extremely rare.”

“How rare?”

“I never came across a serial killer like it.”

Except once, came the voice in his head. He quickly pushed the voice far away.

“If we can get a fix on this guy,” Lash went on, “we can compare it against criminal records. Look for a match. Meanwhile, have you thought about keeping a sharp eye on the other four supercouples?”

“We can’t do a close surveillance for obvious reasons. And we can’t provide adequate protection until we know exactly what’s going on. But yes, we’re already getting teams in place.”

“Where are the rest located?”

“All across the country. The closest couple, the Connellys, live north of Boston. I’ll have Tara get you brief reports on all of them.”

Lash nodded slowly. “You really think she’s the right person for me to work with?”

“Why do you ask?”

“She doesn’t seem to like me. Or else she’s dealing with some issues that are distracting her.”