Police department requests voice lie detector test

McMinnville officials will be discussing the purchase of a voice stress analyzer. The device will be used by McMinnville Police Department as a lie detector.

The department plans to use the device as just one more tool to help officers provide the most effective law enforcement possible.

‘We strive to offer the citizens of McMinnville the best police department we can,’ said Police Chief Charlie Sewell. ‘To do that, we need to equip ourselves with the best tools we can to better protect the citizens of McMinnville.’

Computer voice stress analysis is a controversial technology that attempts to examine and measure a physiological stress component, by extracting micro tremors from the voice and measuring their amplitude.

All muscles in the body, including the vocal chords, vibrate in the 8 to 12Hz range. When a person is being honest, the average sound in that range is generally below 10 Hz, but is usually above 10 Hz in dishonest situations.

Simply put, in moments of stress, like when lying, the body prepares for fight or flight by increasing the readiness of its muscles to spring into action.

The voice’s vibration increases from the relaxed Hz range to the stressful 11 to 12Hz range.

The device is being used more and more by police officials. Although some doubt the accuracy of the results, Sewell has found them to be helpful.

‘They are very accurate,’ said Sewell. ‘This is just a tool to further an investigation. Primarily, it will be used in situations in which the detective feels someone isn’t being completely honest.’

Tennessee has not banned the use of the device, but 10 states have: Illinois, Oklahoma, Michigan, Texas, Vermont, Virginia, South Carolina, Kentucky, North Dakota and Oregon. In the states where the device is allowed, much like the polygraph, it is not admissible in any court of law.

Computer voice stress analysis will be used to help determine the truthfulness of people during investigations. Because of this, two senior detectives will be attending training in September in Nashville.

Besides being helpful in conducting investigations, the department can use the device in pre-employment screenings. Although some regulations restrict what can be asked, inquires about jobs that were not put on the application, terminations, resignation in lieu of termination, disciplinary problems, falsification of application, and employee theft can be.

The complete program includes a laptop computer, software and microphone package to catch deception. The cost of one package is already in the department’s budget, $9,995, but permission must still be given before the purchase can be made at this time.

The Safety Committee will be discussing the request at 6 p.m. this Tuesday.