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Is it the voice of bin Laden?

From Henry Schuster

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A newly released audiotape allegedly has Osama bin Laden praising attacks in Bali and Moscow. CNN's David Ensor and Mike Boettcher report (November 12)
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ATLANTA, Georgia (CNN) -- U.S. intelligence experts are analyzing the latest audiotaped message purported to be recorded by Osama bin Laden to determine if the voice is that of the world's most wanted terrorist.

The identification process comes down to two methods: man or machine.

The CIA, FBI and National Security Agency have computers that use special programs to identify voice prints. The idea is that every voice has a unique pattern like a fingerprint.

Computers can break down the frequencies and harmonics and other possible patterns of someone's speech. (Graphic: Voice analysis)

Those attributes are thought to be unique because the construction of everyone's mouth, nasal cavities and larynx is different and because everyone uses muscles differently to articulate words.

Voice prints require matching the same phrase to the same phrase and between 10 to 20 words or phrases, known as exemplars, are needed to get meaningful results, according to Bruce Koenig, who performed audio and video analysis for the FBI for 21 years.

A non-Latin based language can be even more difficult to analyze and a translator is a necessity, said Koenig, who is now president of Bek Tek, a firm based in Clifton, Virginia.

Among his clients was the Office of Independent Counsel for which he worked on the Linda Tripp tapes, and he was on the National Archives committee that evaluated the infamous 18.5-minute gap on the Nixon Watergate tapes. He also does contract work for the FBI and other agencies.

Koenig said he doesn't think the computer-based methods are as conclusive as humans because of variables such as the quality of the tape and method of recording it.

The voice expert believes the most accurate mode of identification is someone who knows the person well or who has listened extensively to tapes of his voice.

That familiarity method of voice recognition is used in courts of law and are often the basis for identifying people on court-ordered wiretaps.

Hisham Melham is the Washington Bureau Chief of the Lebanese Newspaper As-Safir. He has heard bin Laden speak over the years and offered his opinion on the tape.

"Yes, it sounds like him, but the voice is not as soft as previous tapes by Osama bin Laden, and delivery is not as slow as previous delivery," said Melham. "I really can't say with any degree of certainty that that's him."

"The diction is clear. The content is similar obviously, but it didn't strike me the first time, the second time, that that's Osama bin Laden," he said.

"That soft spoken diabolical voice, if you will, attracted some people, obviously, and because it was as distinct as I said earlier, and that's why when I heard it the first time it didn't hit me as this is the authentic Osama, but I could be wrong," said the journalist.

U.S. intelligence experts plan to play the latest alleged bin Laden tape for al Qaeda suspects detained at Guantanamo and other places around the world.

Sources told CNN they did this last month after audio tapes appeared from bin Laden and his deputy, Ayman al-Zawahiri. The tapes were played for a number of detainees, including Abu Zubaydah and Ramzi Binalshibh.

The investigators want not only to identify the voice but also to determine if the tape contains coded messages.

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