Voice Expert DEBUNKS 'bin Laden' Tape
"The more I work on this, the more I'm confident that it's not him," says Hervé Bourlard, director of the Dalle Molle Institute for Perceptual Artificial Intelligence, one of the world's leading voice-recognition institutes. He wonders if U.S. officials have ulterior motives when they insist it's bin Laden's voice on the tape. "I think it's a good way to scare people so that they're more ready to accept a war on Iraq," he says.
Debunking the bin Laden tape
Voice detective wonders why U.S. called it genuine
MARTIGNY, Switzerland—In this sleepy hamlet at the foot of the snow-capped Alps, the mysterious fate of the world's most wanted man takes the form of coloured patterns and frequency signals generated by an ominous drone.
"You will be killed just as you kill," threatens the voice, purportedly that of Osama bin Laden, specifically naming Canada and other Western countries as targets.
The sound lights up a computer screen with clusters of vertical lines and patches of blues and greens, making a "voice print" that is matched against others confirmed to be the Al Qaeda leader's.
"The more I work on this, the more I'm confident that it's not him," says Hervé Bourlard, director of the Dalle Molle Institute for Perceptual Artificial Intelligence, one of the world's leading voice-recognition institutes.
Bourlard's conclusion — that the tape is probably the work of an imposter — caused a worldwide sensation on Nov. 29 and rekindled the mystery of whether bin Laden is dead or alive.
It also raised questions about U.S. intelligence, which declared the mystery solved by describing the audiotape, broadcast Nov. 12, as "genuine" and recently recorded.
Bourlard stresses he's no political analyst. Still, he wonders if U.S. officials have ulterior motives when they insist it's bin Laden's voice on the tape.
"I think it's a good way to scare people so that they're more ready to accept a war on Iraq," he says.
Terrorism specialists insist Al Qaeda remains a deadly network, with or without bin Laden.
"Losing bin Laden would be a blow to the organization, but not a crippling blow," says Paul Wilkinson, chair of the Centre for the Study of Terrorism and Political Science at St. Andrew's University in Scotland.
Wilkinson says recent attacks indicate Al Qaeda has become more decentralized, with the choice of targets and plots being left to the local extremist groups that make up the network.
He says the most recent overall strategy of targeting tourist sites is likely the work of bin Laden's top deputy, Ayman Zawahiri, an Egyptian doctor and founder of the radical Egyptian Islamic Jihad.
The strategy reflects tactics used in Egypt by Zawahiri's extremists, most spectacularly in the 1997 massacre of 58 tourists at the Luxor temples.
Still, the fate of the Saudi millionaire suspected of masterminding the Sept. 11 attacks remains a gripping and much-debated mystery.
Since U.S. President George W. Bush launched his war on terror by wanting bin Laden "dead or alive," the $25 million (U.S.) reward for information leading to his whereabouts remains unclaimed.
The "balance of probabilities," Wilkinson says, is that bin Laden is alive, perhaps ill, and hiding in the tribal-controlled hills along the Afghan-Pakistani border, "where you can lose an army, let alone an individual with a few retainers."
The last firm evidence that bin Laden was alive came on a videotape dated Nov. 9, 2001. It showed a gaunt and weak bin Laden seated at dinner with Zawahiri, fuelling suspicions that he had been wounded in the U.S.-led war in Afghanistan.
A month later, U.S. intelligence picked up his voice on radio messages in Afghanistan's Tora Bora cave complex but didn't find him when American forces bombed and stormed the site.
For the next year, not a word was heard from bin Laden.
Then, on Nov. 12, the Qatar-based Al Jazeera television network broadcast barely two minutes of unedited audiotape that sent shivers around the globe.
A voice that sounded like bin Laden's praised recent attacks, including the bombing of tourists in Bali, the killing of a U.S. Marine in Kuwait, the bombing of a French oil tanker off the coast of Yemen and the siege of a Moscow theatre by Chechen rebels.
"Our intelligence experts do believe that the tape is genuine," White House spokesperson Scott McClellan told reporters six days later.
McClellan added that the poor quality of the recording made it impossible to verify the voice with 100 per cent certainty.
He called the audiotape "a reminder that we are at war on terrorism ... that we need to continue doing everything we can to go after these terrorist networks and their leaders wherever they are, and we will."
Some Democrats in Congress argued the tape was proof that Bush had failed so far in his war on terror and America shouldn't be diverted from its goal by a war on Iraq.
The Washington Post said the audiotape was tested by linguists at the National Security Agency, who have been analyzing recordings of bin Laden's voice for years. It said intelligence officials had "no doubt" the voice was bin Laden's.
Eleven days later, the Dalle Molle institute — in a study commissioned by the France 2 television network — released data suggesting the tape was the work of an imposter.
The news propelled the 70 computer scientists at the semi-private, non-profit institute into the spotlight. Dalle Molle's Web site crashed for two days under the weight of thousands of people trying to access it for more information.
For researchers who work in public anonymity, the burst of attention is unsettling.
"We're getting fed up with all the publicity," says Bourlard. "We want to stop talking about it and get back to our regular work."
Part of the institute's international reputation comes from developing security systems that use "voice-recognition" programs. In a contract for the DaimlerChrysler carmaker, the institute is creating a system in which access to buildings and rooms is gained by using number codes and speaking into a computer.
Dalle Molle is on the cutting edge of the high-tech world the U.S. government is keen to use in its war on terrorism. Bourlard, who is also a director of the International Computer Science Institute in Berkeley, Calif., says his American colleagues developed computer systems that allow the U.S. government to monitor all e-mails, faxes and telephone communications in the country.
The computers doing the "listening" are programmed to detect key words that might suggest a terrorist plot is being hatched.
"It's illegal for a human being to sit and listen to all that personal communication, but is it illegal if a computer is listening?" asks Bourlard, venturing into the uncharted waters of high-tech anti-terrorism work.
Bourlard's institute has received some U.S. government contracts and he now wonders if the results of his bin Laden study will cause those commissions to dry up.
For the bin Laden analysis, the institute designed a study that is accepted by experts in voice recognition as scientifically sound.
The France 2 network gave Bourlard's team 30 recordings of bin Laden's voice, running for 1 1/2 hours. Some of the recordings also contained the voices of bin Laden associates.
The research team split the recordings into two groups of 15 that contained only bin Laden's voice. A third group of 14 recordings captured non-bin Laden voices extracted from the tapes.
A fourth set featured two recordings made by a member of Bourlard's team, speaking in fluent Arabic and trying to impersonate bin Laden.
One group of the authentic bin Laden recordings was fed into computers, creating a voice print of the frequency and pitch emitted by his vocal chords.
The other three groups of tapes were subsequently fed into the computer one at a time and the computer decided which of the 31 tapes matched the print of bin Laden's real voice.
The computer got all of them right, except for one. It wrongly classified an authentic bin Laden recording — one of extremely low-quality sound — as carrying the voice of an imposter.
Further testing found the computer analysis to be at least 87 per cent reliable — which, to a scientist, leaves significant room for caution. But Bourlard reinforces the institute's cautious conclusion with less scientific observations.
If the subject of the world's biggest manhunt wanted to break a year-long silence, he asks, why wouldn't he use a videotape to prove he's still alive?
And if bin Laden is too sick to appear on video, then why make the most dramatic revelation in years with a recording of such poor quality?
The voice frequency on the tape hovers at a level of 2 kilohertz. That compares to a level of 10 kilohertz for a recording made in a studio and 4 kilohertz for recordings taken off a telephone line.
The 2 kilohertz level is consistent with those achieved when someone tapes a voice coming from a walkie-talkie. But why wouldn't bin Laden talk directly into a microphone or tape recorder instead?
Bourlard believes the use of poor quality, low-frequency sound was no coincidence.
"The easiest way to fake a voice is to do it with a poor quality recording, like off of a walkie-talkie," he says. "The more you reduce the frequency, the easier it is to pass yourself off as somebody else."
Still, he notes the system could have made a mistake. Bin Laden's voice hasn't been recorded for more than a year — a period in which a voice can easily change, especially if the speaker is ill.
Bourlard says many more examples of bin Laden's voice would be needed to arrive at a more definite conclusion.
"If someone put a gun to my head and told me to choose, then I would say it's not bin Laden," he says. "There's certainly more evidence to say that it's not him."
But not enough evidence to decide that the mystery is solved.
address: Toronto Star
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