The Lie Detector is Nothing More Than a Police Setup

This article might be about the trouble with polygraphs inside the Chicago police department, but the lessons learned apply to anyone charged with a crime in the U.S. The state in which we defend people charged with crimes (Texas) is one with severe punishment - and if you've been accused of committing a violent crime or any other crime, you better make sure the police are following the rules.

Because when they don't, the consequences can mean a wrongful conviction.

Beware the 'Pre-test Interview'

Coercing a false confession out of a suspect is similar to unlawful search and seizure in drug cases, from the perspective that the police have constitutional boundaries that should not be crossed, but sometimes are.

As Duaa Eldeib reports for the Chicago Tribune, the police may have been using the polygraph machine as a way to get false confessions out of suspects. Take Donny McGee, for example. He was charged with the murder of a neighbor but later cleared by both a jury and DNA evidence.

Yet, earlier, the police somehow managed to get a "confession" out of him, even though he was in the room for a polygraph and never even took the test.

It all boils down to the pre-test interview, which, according to Eldeib's report, should consist of explaining the polygraph, getting consent, and reviewing the questions to be asked.

However, rather than following standard polygraph procedure, court documents allege that the police examiner would berate, threaten, and lie. This would, in turn, lead to false confessions.

Confessions Admissible in Court

A confession, false or otherwise, is a damaging piece of evidence. In many states, prosecutors cannot introduce polygraph evidence in court, but they can use confessions that the police get out of suspects, even though the polygraph may have been used as a tool to get that confession.

Local rules often state that's exactly what the police cannot do, and if the polygraph test is not done correctly and/or a false confession arises out of it, an innocent person can be wrongly convicted.

In Texas, polygraph results are generally not admissible in court. Even if they were, it takes some measure of skill to correctly administer a polygraph test, so that the evidence would mean something. The polygraph test measures stress, not lying, according to Diane Jennings with the Dallas Morning News, so there's a good chance for false positive results.

Ignored Standards for Polygraphs

Eldeib reports that the Chicago P.D. has systematically ignored standards for polygraphs, often getting false confessions during the pre-test. According to the American Association of Police Polygraphists, basic pre-test standards include:

  • Getting consent and advising of rights related to polygraph testing
  • Not doing the examination if the subject isn't in a suitable condition to be tested, either mentally or physically
  • Maintaining an objective approach throughout the test

This isn't even the whole list of pre-test standards, but consent, suitability, and objectivity are three big ones. And if someone has been threatened and lied to during the pre-test, it's clear that some cops simply don't care much about standards.

Speak to a Texas Criminal Defense Attorney

If you've been arrested or charged with a crime in Texas, or a federal crime, contact the Dallas lawyers of Crain Lewis Brogdon, LLP.


Polygraphs and false confessions in Chicago

Use of polygraphs grows in Texas


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