Читать книгу The Assassin - Andrew Britton - Страница 16

“This is going to take forever,” Naomi finally said.

“Not forever,” Liz Peterson replied. She shot the younger woman a teasing grin and said, “But close.”

They were seated in identical chairs in a secure room on the fourth floor of the Ministry of Defence, a nondescript eight-story building faced in pale Portland stone. The room was cool, dim, and windowless, which didn’t bother Naomi in the least, as the sight of rain drifting over the city for the third day in a row would not have improved her sour mood. They had been staring at the computer screen for nearly two hours now, and the young CIA analyst was beginning to think they were chasing a ghost.

As Peterson worked the keyboard, Kharmai studied the equipment laid out on the table. She was somewhat surprised at the quality of the MoD’s spectrograph equipment, though she didn’t know why this should be. If anyone could come close to matching America’s bloated intelligence budget, it was the British. Some of the specific innovations were new to her, but she knew the process inside and out; after all, it was Bell Labs, her first employer, that had pioneered the use of voice-recognition technology back in the 1940s. Things had come a long way since then. Significant advances over the past few decades had done away with the cumbersome magnetic tape and photographic paper of the analog spectrograph. Digital signal processing, or DSP, had since taken its place, though in some ways, the new equipment was almost as tedious to use.

The British computer engineer caught her curiosity. “Have you guys replaced all that junk your contractors came up with in the sixties?” she asked, with a smile. Peterson knew about Naomi’s years before the Agency.

“I couldn’t really tell you,” Kharmai replied honestly. “We obviously don’t have anything as good over here, but I’m not sure about Langley. Last time I checked, they had a contract with Motorola in the works, but I’m not sure if they ever bought the gear.”

“If your Admin Directorate had anything to do with it, they probably decided to look for something cheaper. Our budget people are the same way; they’d take the cost of this stuff out of our salaries if they thought they could get away with it.”

Naomi smiled in agreement. Liz Peterson was the “man in mind” she’d mentioned to Emmett Mills the previous day. She had first met Peterson at an embassy function shortly after arriving in-country, and they had hit it off immediately, despite the fact that they were technically competitors. On the weekends they frequently met for drinks at the Dorchester Hotel, and while they genuinely enjoyed each other’s company, both women habitually took those opportunities to dig for a little information. They both knew it was part of the job, and they took it all in stride. Naomi was well aware, for instance, that her access to Whitehall’s database had been approved by somebody much higher on the pay scale than Liz Peterson, despite the informal nature of her request. She also knew that whatever they managed to turn up would soon land on the prime minister’s desk, most likely within an hour of discovery. Sharing information with one’s allies was the cost of doing business, but that wasn’t much of a price to pay, especially when they managed to come up with something interesting.

Peterson sat up in her seat as the numbers paused on the monitor. Fixing her pale blue eyes on the screen, she brushed a strand of blond hair out of her face and brought up the relevant information.

“You have something?”

“Maybe,” Peterson replied, a hint of excitement coming through. She leaned forward and traced the amplitude waves with her index finger. “Just going by the visual, that’s a…sixteen-point match.”

“Good enough for a probable,” Naomi murmured. After purchasing their first analog spectrographs in the late 1970s, the CIA’s Directorate of Science and Technology had adopted, for lack of a better system, the forensic standards used by U.S. law enforcement at the time. A “probable” identification was assigned to any match greater than fifteen but less than twenty points on a given spectrogram. In other words, there was an 80 percent chance that the voiceprint in the MoD’s database matched the voice found on the tape in al-Umari’s Knightsbridge home.

Peterson was still trailing her finger along the screen. On the monitor, the voiceprint resembled the cross section of a series of waves. “See here,” she said, pointing to a large splotch of red in the left-hand corner of the graph. “That’s a hard c, like in the word ‘car.’” She moved over to the right-hand side of the graph, where the red was much less pronounced. “And this is a soft t, like in ‘booth.’ The fricatives you see here are really good news for us.”

“Because of the language difference?”

“Right. You tend to find a lot of allophones in the Arabic language, and they sometimes lead to false negatives on a spectrogram, even after you convert from analog to digital and filter out the elec—”

“Hold on,” Naomi said, a little exasperation creeping into her voice. “I understand the technology, Liz, but I have no idea what you just said.”

“Allophones?” Kharmai nodded meekly, causing Peterson to smile. It wasn’t often that her stubborn friend could concede when she was lost. “Well, a phone is a sound that has a definite shape as a sound wave, which is obviously really helpful when you’re trying to match voiceprints. An allophone, on the other hand, is one of several phones in a phoneme. If you change one phoneme in any given word, you can produce another word entirely.”

“So a phoneme is like…a syllable?” Naomi asked.

“Not really. More like the way in which syllables are put together. But as I was saying, the problem with allophones is that they can lead to false negatives. This happens for two reasons. First, the software is good, but it isn’t that good. It can’t always differentiate when two phones are that similar. Second, you’re always going to have some electronic interference. Part of this occurs when the recording is actually made. In this case, we had to deal with distortion on the recording device and interference on the line itself.”

“Also, you lose some of the source material when you convert from analog to digital, right?”

Peterson flashed Naomi the kind of smile a teacher reserves for her star pupil. “Exactly. We use filters to remove electronic noise outside of the desired frequency range, which helps, but you still lose some of the original conversation in the measurements.”

Naomi shrugged. “Eighty percent is good enough for me. What’s the background?”

The other woman minimized the spectrogram and double-clicked on the numerical file. Instantly, the screen filled with information.

“Voiceprint 243.55 belongs to…Abdul Rahman Yasin.” Peterson sucked in her breath as her eyes scanned the screen. “God, this guy is right up there. Wanted on nine counts by the FBI. Involved with the PMOI in Iran in the early nineties, suspected collusion in the WTC bombing in ’93…He matches your profile, Naomi.”

Kharmai leaned in to get a closer look. “Except for the languages. He doesn’t speak German, and he learned Arabic in Tunisia. That’s the Maghreb dialect, and we typed the voice on the tape as Gulf Arabic.”

Peterson shot her a sideways glance.

“What?” Naomi asked.

“You didn’t mention the German. Where did you get that?”

Kharmai winced. “Sorry. That came from the Babylon Hotel. We’re pretty sure this guy Kohl is the second voice, but it’s almost certainly an alias, because the Germans don’t have any contractors by that name in the region.”

“So he speaks Arabic and German. That should narrow it down.” Peterson cleared the screen and began typing in the new parameters.