Should I take a polygraph (lie detector) test?


Polygraph tests also known as “lie detector” tests can be invaluable tools as part of a strategic criminal defense. While law enforcement may use polygraph tests to try to pin a crime on a suspect, aggressive criminal defense attorneys can use polygraph results to show a client’s innocence. Further, in many situations the results of a polygraph test can be challenged. Understanding the strategic use of lie detector results is key to a vigorous defense.

The Criminal Defense Lawyers At Grabel & Associates Have Used Polygraph Results To Keep Charges From Being Filed

At Grabel & Associates, our attorneys have years of experience working with polygraph results. We understand how to challenge polygraphs results in some cases the questions may be flawed, or the testing circumstances are disruptive. Other times, the data may not be correctly interpreted. In addition to challenging results, as the top criminal defense law firm in Michigan, we have also successfully used the most reputable private polygraph analysts to provide compelling proof of our client’s innocence in some situations ensuring criminal charges are never even filed.

The Basics Of Michigan Polygraph Testing

In many Michigan criminal cases, suspects are asked to submit to polygraph testing. A polygraph machine is used to detect when a person is lying by recording the body’s involuntary responses to questions. Polygraph tests are based on the notion that when people lie their body will respond in certain ways.

In order to measure people’s reactions, generally four to six sensors are placed on the person being questioned. The sensors measure:

  • The suspect’s pulse
  • The suspect’s breathing rate
  • The suspect’s blood pressure
  • Whether the suspects perspires
  • A suspect’s body movements

Polygraph tests can be used in any circumstance, but are frequently used in criminal investigations to determine an individual’s knowledge of, or participation in a particular crime, or other questions that a police officer may deem relevant. Polygraph tests may also be useful as part of a vigorous criminal defense. The results are not only used to show that someone is lying, but can also be an effective way to show that someone is telling the truth.

The exam consists of three parts:

  • The pre-test interview (where sample questions are asked to get a baseline)
  • Chart collections (where the polygraph sensors are placed on a person’s body and test questions are asked)
  • Review of the chart (the examiner will determine if you passed: “no deception indicated,” or failed: “deception indicated,” or if the test was inconclusive)

The test typically lasts around two hours. At the beginning, the participant will be asked a handful of basic questions to establish a baseline reaction. The person’s reactions will be measured throughout questioning and recorded on a piece of paper. The polygraph examiner will review and compare the person’s vital signs to their baseline, looking for significant changes. When a significant increase is detected, a person is considered to be lying.

What Kinds Of Polygraph Questions Can I Expect?

The most common type of polygraph test used in Michigan criminal investigations is the Control Question Test (CQT). The CQT test compares your reaction to relevant questions(i.e. “Did you steal the car?”) to your response on control questions. The type of questions asked may alternate between those that are relevant to the investigation, those that are irrelevant, and “control questions” that are designed to elicit some sort of physiological response (i.e. “Have you ever lied to get something you want?”).

Another type of polygraph questioning is the Guilty Knowledge Test (GKT). The GKT involves multiple-choice questions that only someone who is guilty could answer correctly.

Our Michigan Criminal Defense Lawyers Have Experience Using Polygraph Analysis In All Types Of Michigan Criminal Cases

While polygraph/lie detector tests still have some skeptics, the results of polygraph testing are generally admissible in Michigan courts. This means it is crucial that a criminal defense attorney be prepared to challenge polygraph results. The Michigan criminal defense lawyers at Grabel & Associates understand that certain polygraph settings are more reliable than others, with many factors affecting how reliable the results are. 


Our Michigan Criminal Defense Lawyers Have Years Of Experience Using Lie Detector Tests To Prove Our Clients’ Innocence

These include anything from the particular examiner, to the types of questions used, to the person being questioned. Some people may be more anxious than others, leading to false positives. Further, as the top criminal defense law we have access to the most qualified polygraph examiners in the state whose results will stand up to scrutiny and will use polygraph tests as part of your vigorous defense.

Polygraph Test Resources In Michigan Include:

The attorneys at Scott Grabel & Associates are available 24 hours a day, seven days a week to discuss your criminal case and whether the use of a polygraph test would be beneficial to you getting the best possible result in your case. For a free initial consultation, call us, toll free at 1-800-342-7896, or use the contact us form on this website.