Swiss tests cast doubt on whether terror tape was from Bin Laden

Tests on the latest audiotape statement attributed to Osama bin Laden showed the speaker was an impostor, though insufficient data left the test inconclusive, the head of a research institute said yesterday.

Herve Bourlard, director of the Dalle Molle Institute for Perceptual Artificial Intelligence in Martigny, Switzerland, said he tended to agree the tape, first aired two weeks ago, did not feature the voice of the long- absent terrorist leader, but the margin of error was too great to be absolutely certain. "If I had a gun to my head and was forced to lean one way or the other, I'd say it wasn't bin Laden," M Bourland said.

The review of the tape was commissioned by France-2 television, which provided two hours of videotape recordings of bin Laden, his accomplices and other Arab speakers. The institute created a computerised model of bin Laden's voice from video recordings. To verify the reliability, scientists tested that model with recordings from bin Laden and others that were not.

The computer made one error in 20 tests conducted, M Bourlard said, mistaking bin Laden's voice as a fake. "That's a lot. We worry because there were so few samples to create the model with and only 20 samples to test with. One mistake in 20 is not very reliable."

The CIA and the National Security Agency believe the tape is bin Laden.