'Innocent Until Proved Guilty?'

March 30, 2006 — -- A Pentagon study obtained by ABC News finds that a new kind of voice lie detector used by the U.S. military and American police departments is no better than "flipping a coin" in detecting lies.

Until the Pentagon ordered a halt to its use, the Voice Stress Analyzer was being used by military intelligence interrogators at Guantanamo Bay and in Iraq. Several suspected terrorists were released from custody based on the machine's results and former Iraqi deputy prime minister Tariz Aziz was one of the many "high value targets" who were hooked up to the now discredited machine.

A laptop, microphone and software program make up what is called the computer-voice stress analyzer, or CVSA. Used by police departments across the country, this lie detector is a foolproof system to help catch criminals and liars, according to the man behind it.

"Police departments have paid $10,000 per system over the last 18 years and rely on it exclusively for truth verification," said Charles Humble, chairman and CEO of the National Institute for Truth Verification, which sells the CVSA. "We have a remarkable record of success."

But as questions surrounding the scientific validity of the machine and Humble's credentials grow, not everyone agrees that that should be the case .

After Michael Crowe's 12-year-old sister, Stephanie, was found stabbed to death in her bedroom, the Escondido, Calif., police department brought him into the station for questioning and hooked him up to the CVSA in the middle of the night.

From tapes recorded during his questioning, Crowe answered "Yes" when the detective asked, "Is today Thursday?" But when Crowe replied "No" when asked whether he took Stephanie's life, the detective told him that he had failed the test.

"I started to think that, you know, maybe the machine's right, especially when they added on top of it that the machine was getting my subconscious feelings on it, that I could be lying and not even know it," Crowe, now 21, told "Primetime." "They said the machine is more accurate than the polygraph and is the best device for telling the truth, for finding the truth."

Once the detective told him that he had failed the test, Crowe said he began to doubt his own memory and wonder whether he might have killed his sister.

"I didn't want to go to prison, and I just wanted to be out of that room," Crowe recalled. "So my only option was to say, 'Yeah, I guess I did it,' and then hope for the best."