“But not now?”
“Right. Thanks to the special headphones you’re wearing, it’s currently only capturing the words of Bob Marley.”
Thornton tapped his head to indicate the implanted device. “I’m guessing this isn’t something you can pick up at a Radio Shack.”
“As you know, the NSA is the world champ of eavesdropping gizmos, or at least that’s what I would have bet my life on until five minutes ago, but this capsule is a decade more advanced than any I’ve ever seen.” O’Clair pointed from compartment to compartment on the image generated by the screen. “A capacitor powers a microcomputer, which runs the mic and the transmitter — standard stuff. The unique thing is what it’s missing: There’s no power source.”
“No nine-volt battery?”
“Possibly the capacitor is charged by the movement of your head, the way a watch works. Or maybe it uses the temperature differential between your body and outside air, transforming the heat flow into electricity. I didn’t even know it was possible to miniaturize an energy harvester.”
His suspicion of an eavesdropping device confirmed, Thornton had a flood of questions. “Any idea how long it’s been in there?”
“I’d say at least six weeks because there’s no trace of inflammation.”
“From what?”
“A simple injection, probably, maybe while you were asleep. Probably they hit you with ketamine first to make sure you stayed asleep. Off the record, we use ketamine. Hardly anyone has any reaction to it.”
An odd thought struck Thornton. “Could they have used midazolam?”
“Sure. Midazolam’s just a stronger version of Valium,” O’Clair said. “The nice thing about ketamine is it gives the targets incredibly vivid nightmares, which makes for decent cover if you’re in their bedroom practicing dark arts.”
“Could Leonid Sokolov’s murder have actually been a case of midazolam causing a reaction?”
“Oh.” O’Clair’s eyes bulged. “With seven grams of lead to cover it up?”
“What if it had started out as an eavesdropping op?”
“If Sokolov had been drinking an unusual amount, yeah, there’s a chance that the midazolam could have triggered a respiratory depression. You think that’s somehow connected to you?”
“No, what are the odds?” Thornton said, despite a prickly sense that there was a connection. “Here’s a better question: Why hasn’t the thing in my head been picked up by metal detectors?”
“Actually, it appears to be constructed from processed collagen, like absorbable sutures, or maybe a comparable synthetic that the body can break down.”
Thornton gripped the rocky wall to steady his nerves. “Tell me you can get it out.”
“I can get it out. I brought a scalpel and some topical anesthetic. Wouldn’t take a minute. Whoever installed it will know, though.”
“Why can’t we short it, making it seem like the device failed? Hardly a stretch, given I received a major blow to the head, right?”
“Yes. Evidently it was the swelling that jogged the thing out of its bed atop your temporal bone. If not for that and your pre-op haircut, you would have never detected it. The issue is, after we take it out, we can’t reinsert it.”
“Why the hell would we want to reinsert it?”
“To find out who put it there. Once the device is out, we can’t reactivate it without them knowing it. Then we’ll have no chance of tracking them.”
His eyes having adjusted to the dark, Thornton saw that the underground train station was enormous, yet he was starting to feel claustrophobic. “And if we don’t take it out?”
“We would need to find another person implanted with the same kind of device, or, at the very least, we would need a second functioning device.”
“Why?”
“The thing needs to transmit via cell phone stations. It sends your conversation as a data package.”
“Can’t you just track the data to the recipient?”
“Yes and no.”
“What’s the yes part?”
O’Clair sighed. “You need to understand the no part first. If you looked at it on a computer screen, the audio you’re transmitting would be represented by a distinctive N-log wave, a signal sequence that looks like a seismograph readout. The problem is that you wouldn’t have any way of knowing which signal is yours among the hundreds of thousands of other signals in the vicinity, generated by everyday cell phone conversations or radio-controlled toys or bar code scanners.”
Thornton pointed to his head. “So the signal coming from me would look like a fish in an ocean full of indistinguishable fish?”
“Exactly. But if we had a second device in the same room as you, transmitting the same audio, then we would be generating two identical signals that a computer could pick out from the rest of the fish. From that point, a high school student could track the data.”
“But we don’t know if a second device even exists. We can’t just somehow scan people for it, can we?”
“Yes, actually, with a radio-frequency detector available at Radio Shack for about fifty bucks. The only problem is we’d get a false positive whenever a person had a cell phone on them.”
“In other words, every time?” Thornton said.
Nodding, O’Clair aimed the flashlight down the tunnel. The steel drums emanating from the speaker could have concealed the approach of a marching band. There was no movement, no unusual shadows. “What we can do is run an old-fashioned counterintelligence op,” he said.
He’s spent too much time among spooks, Thornton thought. “Like what?”
“If you went to, say, a Metallica concert in Madison Square Garden, the recording device would still pick up everything you say.”
“Filtration?”
“The energy harvester in this thing is a greater leap in technology than a car that runs on a couple double-A batteries. So I’m guessing that whoever developed it solved the issue of conflicting audio — like a foghorn on the Staten Island Ferry. But you could temporarily jam the recording device.”
“With a radio jammer?”
“Right.”
“How does that work?”
“It floods the eavesdropping device with a strong radio signal across a large part of the frequency spectrum so that the weaker signal from your conversation is essentially lost.”
“If you’re shooting a radio jammer at my head, wouldn’t whoever’s monitoring know what you’re up to?”
“Not if you went someplace where transmissions are jammed all the time.”
“Like at a radio station with a strong transmitter?”
“Yeah. Any significant source of electromagnetic interference could work. You would just need to be close to it.”
“But if I went to a place like that, my personal Big Brother would know I’m onto him, and he’d send his associate with the Ruger.”
“Not necessarily. If we play it right, Big Brother wouldn’t know you’re onto him, although he might suspect it — which would work for us. After we get out of here, simply tell me you have a meeting with someone from the agency. We’ll pick a place next to a radio station.”
“Which agency?”
“Doesn’t matter.”
“I guess the more ambiguous, the better,” said Thornton.
“Now you’re getting it.” O’Clair smiled. “You tell me the person contacted you — just don’t say how. To add verisimilitude, I’ll send you an anonymous gobbledygook Hushmail beforehand that the eavesdroppers could interpret as an encrypted message.”
Thornton was uneasy. “When I texted you this morning, I was hoping you would take me to your office — bring me in out of the cold, as it were — and let the professionals take over.”
“Now you need to stay away,” said O’Clair. “There’s a chance NSA is behind this. Since the Patriot Act, the only rule has been Don’t get caught. But even if we were as sure about trusting the NSA as we are about the sun coming up tomorrow, you know how it would play out — and this is true if you go to any of the agencies: You’d spend a day or two being polygraphed, then the brief would be cabled to heaven knows how many divisions, whose representatives would need to have an internal meeting and, after that, interagency meetings, and, finally, you’d get sent to someone in Tech who will know less than we do already.”