"Could you take a look at her office?"

"Doubtful. It's right off a college computer lab, and there are always people around there, day and night. Not right in her office, but up and down the hall and around the lab."

"We've got to get those disks, before she does something with them."

"We don't know what to do, other than watch her. We could snatch her, and squeeze the disks out of her, but, man. if she disappeared, that might be one too many accidents even for the Dallas police. Also, there's been a guy hanging around with her, maybe a boyfriend or something. It's like she doesn't want to be alone."

Corbeil thought for a long time, Hart waiting through the pause. As he thought, with the CNBC mimes doing their silent chat opposite his desk, it occurred to Corbeil that he'd like to fuck every single one of the reporting women, but as for stock information, he wouldn't trust any of them as far as he could spit a rat. That was not a coincidence, he thought. That was marketing. He wrenched himself back to the problem: "So keep an eye on her. Monitor her."

Hart was disappointed; Corbeil could hear it in his voice. He didn't say "That's it?" but he wanted to. Instead, he said, "We can't really hang around her neighborhood, but if you want to cough up a couple of grand, in cash, I can put a bug on her car. At least we'll know where she goes."

"Do it. I'll send the cash through American Express. I'll find out where the local office is out there, and you'll have the money in a couple of hours. How long will it take you to get the bug?"

"Probably tomorrow. I'll have to call around."

"Good," Corbeil said. "One other thing. I want you to start e-mailing reports to me. I've set up a new account called, um, Arclight. A-R-C-L-I-G-H-T. Regular number. Tell me that you're monitoring them, that you're watching them, and ask for advice. I'll send one back that tells you to watch them for another week, to see if they make any contacts that seem to reflect an association with Firewall. We can discuss the feasibility of going to the FBI. Don't be overly dramatic, but mention something about national security. We want to sound ethically challenged in the defense of the good old USA."

"Building a paper trail?"

"Exactly. Give me a note or two every day, reporting on the surveillance. Maybe even suggest that we might want to get an ex-FBI guy to do a black-bag job, but I'll turn you down on that."

"All right. I'll get Benson to chip in a report."

"Read it first. He's not the brightest bulb in the chandelier."

When Hart was off the line, Corbeil leaned back in his chair, made a steeple with his fingers, and thought about it. Hart's memos would be useful in a couple of different ways. If everything went smoothly, and they either recovered the disks or discovered there was no second copy, then the memos could stay in the files just as Hart sent them.

If, on the other hand, the situation got out of control, the memos could be altered to show an illegal operation running inside AmMath. The memos could be altered without changing the time stamp on them, and a check of the phone records would show the matching calls coming and going.

Since the Arclight file had been opened from the computer in Tom Woods's office, it would be at least credible that Corbeil didn't know about it; especially if Woods wasn't around to testify.

That's all Corbeil would need: a level of credibility, and the silence of contrary witnesses.

And a good lawyer, of course.

Since I couldn't sleep anyway, I kicked LuEllen out of bed at six-thirty and we went to look for Clarence Mason. We stopped at a diner for cholesterol and caffeine, got clogged in traffic heading into San Francisco, crossed the Golden Gate at eight o'clock, and after a bit of wandering, LuEllen ran into a gas station and got a guess on the location of LaCoste Road. Mason's place was a small dark-green bungalow with an old-style two-track drive. Nobody home.

"Why didn't I think of that?" I said, back in the car. "Most people work during the day." We went out to a phone, and I hooked up the laptop and got online with Bobby. Mason, he said, had his own photography business in Santa Rosa. We found him on the second floor of a downtown building, above a flower store: Mason Restorations.

The office door looked like it might open on a detective office from a noir movie-textured glass with a gold-leaf name. Inside, it was all windows, blond hardwood floors, and high-tech machinery. The place had two rooms-a big working space behind the counter at the entrance, and a small glassed-in office at the far end, along the window wall. The working space was occupied by a half-dozen top-end Macs, a number of film and flatbed scanners and several large color printers. Three women were looking at a computer screen when we pushed through the door; one of them straightened and walked over to the counter.

"Can I help you?" she asked.

"We're here to see Mr. Mason."

"Do you have an appointment?"

"No, but it's fairly urgent." A thirtyish blond man had looked up from a computer inside the glassed-in office; I was willing to bet he was Mason. "Could you tell him we're friends of Bobby?"

"We really need to talk to him," LuEllen said from my shoulder, with a smile.

"Just a minute, please."

She walked back to the glassed-in office, stuck her head inside, and said something; I could see the blond's head bobbing. She motioned to us, and we pushed through the counter gate and down to the office. The woman rejoined the other two, who were looking at the yellowed image of an old woman, apparently scanned from a paper photograph.

Mason stood up, looking unhappy. "I'm not sure if we know the same Bobby."

"If you go online and call him, he'll tell you we're all right," I said.

He swallowed and said, "I'm not online much anymore. Who are you?"

"You saw the list of the people in Firewall? I'm k."

He sat down, and sat perfectly still for a moment, except for his bobbing Adam's apple, then said, "I've heard a couple of things about you. if you're really k. Did you once have a contract with a wine company to help straighten out their distribution system?"

"Yes."

"Then you know my friend Clark," he said.

"Miller," I said. "He lives in St. Helena in a redwood house with a real redwood hot tub in back, and his wife's name is. Tom."

"Ex-wife," Mason said. "She got the house." He looked at LuEllen and said, "Close the door." LuEllen pushed the door shut and we sat down in a couple of wooden visitors' chairs. Mason pushed both hands through his hair and said, "This FirewallI don't know anything about it, but my name is all over the place. It's driving me crazy. What's going on? I keep waiting for the FBI to show up."

I looked at LuEllen, who shook her head. To Mason, I said, "Goddamnit. You don't know anything?"

He spread his hands"Honest to God, I was sitting at my kitchen table reading the paper and eating shredded wheat and scanning this article on the Lighter killing, and all of a sudden I see this list with my name in itomeomi. I almost choked to death. I never heard of Firewall before this thing. Now I'm supposed to be some sort of terrorist."

"Yeah. Me, too. And Bobby. We're trying to figure out what's going on."

Mason looked at LuEllen again. "Are you on the list?"

"No. I'm just a friend. Of k's and Bobby's."

Mason shook his head. "I don't know what to do I've thought about calling the FBI and identifying myself, but. I don't know, I don't think that's a good idea."

"I don't know your history," I said. "I might wait a while before dragging in the law."

"Yeah. So would I." He wasn't a tough-looking guy, but the way he said it suggested a need to stay away from the feds. As a matter of privacy, ethics, and personality, I didn't ask him what he did; LuEllen wasn't so inhibited.