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Police use controversial tech tool on suspects Critics say 'voice stress analyzers' are a scam BY SEAN WEBBY Mercury News Bay Area police departments are snatching up one of the latest technological tools in crime-solving -- a computerized voice analyzer that's supposed to determine when the bad guy is telling a lie, just by the sound of his voice. But critics say this $10,000 device doesn't work; it only intimidates suspects into confessions. Police departments in San Jose, San Francisco, Menlo Park, Mountain View and Redwood City are among about 1,000 agencies that use ``voice stress analyzers.'' The California Highway Patrol uses the machine when hiring officers. Law enforcement agencies have only one place to buy the controversial devices and train their officers at $1,300 per student -- the National Institute for Truth Verification, a private company in West Palm Beach, Fla. Yet many law enforcement agencies refuse to use the analyzers, including the FBI and both the San Mateo County and Santa Clara County sheriff's departments. Several police chiefs and other senior investigators in departments who bought the voice analyzers said privately they doubted that the device measured the truth very well. But all said it did what they had bought it to do -- elicit confessions from suspects who are convinced the machines work. ``It's a marketing scam,'' said Sgt. Gary Hoss, who is the chief polygrapher for the San Mateo County Sheriff's Department. ``It's fast and it's cheap and it doesn't work, and that's the bottom line.'' Hoss and others predict these voice analyzers will put innocent people in jail and expose police departments who use them to massive lawsuits. Yet NITV says its product is more powerful at detecting a criminal's deception than polygraph tests. ``It can't get much more accurate,'' said David Hughes, the company's director and a retired captain from the West Palm Beach, Fla., police department. NITV reports that its analyzer has about a 98 percent accuracy rate. San Jose police used one recently to interview a suspect in an unsolved 30-year-old homicide, according to detective Sgt. Mike Ponte. The analyzer showed he was telling the truth about his innocence, Ponte said. ``It was fast and easy, and we felt comfortable that he was clear,'' Ponte said. The theory is that the voice stress analyzer works by measuring ``micro-tremors'' in the human voice -- inaudible vibrations that speed up uncontrollably when a person is lying. The device's theoretical advantage is that it can be used on tape recordings, phone conversations and even from television shows to determine whether the speaker is lying. Many investigators who have used the machine agree with NITV's pitch that the machines are faster, cheaper and more accurate than polygraph testing. Company officials de-emphasize the few studies done on whether the voice stress analyzer works, because many of the studies have been done by the polygraph industry, the machine's chief critic. The U.S Department of Defense Polygraph Institute in 1996 concluded that the machines have an overall accuracy rate of just under 50 percent. Critics say that analyzers are simply electronic Ouija boards. The detectives who use them, trained to detect lies, see what they want to see in the machines' results. The NITV asks agencies to send to them for training their ``most accomplished interviewing/interrogators available.'' And it is the mistakes that officers will make with the voice analyzer that worry its critics. ``What is more stressful than a person who is being questioned by law enforcement?'' said Brian English, a polygrapher with the Baxter Institute in San Diego. Judges generally don't allow polygraph test results or voice-stress results as evidence in court. Lie detection, judges have ruled, is not scientifically reliable enough. In 1998, a police officer arrested a San Diego teenager on charges of murdering his sister after he failed a voice-stress test. The charges were dropped the next year. Now the boy's family is suing the police, prosecutors and the NITV. A Henderson, Nev., man sued the local police department after it charged him with being an accessory to rape when he flunked a voice-stress test in 1996. The charges against Vincent Sedgewick were eventually dismissed, and so was his lawsuit. |
