Free Consultations | Speak With a Lawyer 24/7 630.261.9098


3 Facts You Need to Know About Illinois Polygraph / Lie Detector Tests

Posted by Dominick R. Dolci | Apr 12, 2018 | 0 Comments

Here's a scenario:

You are being questioned by a law enforcement officer who suspects that you have done something unlawful. The officer is saying one thing; you are maintaining something different.

At one point, the officer requests that you take a polygraph exam. He may ask whether you're willing, or he may imply you have no choice. Either way, you are unsure of what to do and how to protect yourself. Should you comply to stay in the officer's good graces, or should you politely decline? What exactly are your rights? In your mind, each choice could result in terrible consequences.   

Now, what if we told you that a polygraph isn't the terrifying contraption it's built up to be? In fact, if you're armed with the right knowledge, a lie detector test can pose little threat to the ultimate trajectory of your case.

Don't believe us? Here's the knowledge to arm yourself.

Polygraphs 101 - A Primer on Lie Detector Tests 

You're probably wondering:

What exactly is a polygraph? Is it the same as a lie detector? How does a polygraph exam even work? Can a polygraph really detect lies?

Television and movies make polygraphs look like some mystic piece of technology, but it's actually quite a simple device.

Essentially, a polygraph is an instrument which tracks and records the various physiological outputs of your body. These outputs include breathing, heart rate, blood pressure, and the electrical conductivity of your skin's surface.

A polygraph exam is simply an examination conducted with a polygraph. Typically, polygraph exams occur in conjunction with police questioning. During a polygraph exam, a professional examiner monitors the outputs of the polygraph to identify fluctuations and determine whether your answers are truthful. As a result, polygraph exams are often called lie detector tests.  

So, what if you find yourself in a situation where a law enforcement officer is asking you to take a polygraph exam? What then?

The single, most important thing you can do is to stop and thoroughly consider your options. In most cases, taking a lie detector test is far more likely to hurt you than help you. It is important to consider the consequences, which can be severe.  

The following are three crucial details about polygraph exams which you should keep in mind if you are ever asked to take one.

Three Facts You Should Know About Lie Detector / Polygraph Exams

1. You are never obligated to take a polygraph exam, even if asked.

Legally, Illinois law enforcement cannot force you to take a polygraph exam if you do not consent. That is a fact.

When being questioned, law enforcement may try to psychologically intimidate you or play up the benefits of taking a polygraph examination. They may suggest that if you have nothing to hide, you shouldn't have a problem with taking a polygraph exam. They may offer to go easier on you. There are many tactics law enforcement may use to convince you to take a lie detector test.

However, the prime takeaway is that, at the end of the day, whether you take a polygraph or not is 100% your choice.

In nearly all cases, the best option is to not take a polygraph. But, more on that later. 

2. Polygraphs are rarely admissible in court, but they can still hurt you.

The reliability of polygraph exams has been heavily debated in the scientific community. Many scientists still hold the opinion that polygraph readings are far too easily skewed by external factors. Additionally, the results of an exam are subjective to interpretation from the examiner. As it is, there is no failproof physiological sign which indicates someone is lying. In fact, in People v. Baynes (1981) 430 N.E.2d 1070, 88 Ill. 2d 225, the Illinois Supreme Court recognizes the unreliability of polygraphs. 

Because of the significant inconsistencies of polygraph exams, courts are extremely hesitant to admit any polygraph exam results as evidence. Instances where polygraph results are admitted as evidence require the consent of both the prosecution and defendant. Even if admitted, the evidence doesn't always hold up well under cross-examination.  

However, the infeasibility that a polygraph will be admitted as evidence does not mean taking one can't still severely hurt you.

Polygraphs can be particularly useful if an officer wishes to obtain a search warrant against you. In many instances, the results of a polygraph exam can give law enforcement probable cause to search your property. What is found during a search can then be admitted as evidence. So, while polygraph exam results can't be used as evidence, they can aid in procuring evidence to use against you in court.

3. Taking a polygraph exam probably won't help you.

Polygraph exams are a common tactic law enforcement officers may employ to build a case against you. Their ultimate goal is to charge and prosecute you for a crime, and they will use every advantage they have to achieve that goal. Chances are, if an officer asks you to take a polygraph exam, they're asking with an agenda in mind. 

Due to pressure from law enforcement, you may feel that taking a polygraph to prove your innocence will help get you out of an investigation. However, consenting to a polygraph is incredibly risky, because you don't know what the police already know and what information they're seeking. The information you reveal during a polygraph might actually give the police that last puzzle piece they need to obtain a search warrant and charge you with a crime.  

Know this:

The burden of proof rests with the prosecution, and they need strong evidence to charge or convict you. While it's only natural to want to prove your innocence, consenting to a polygraph is not always the best option. In most instances, the simplest and most effective strategy is to avoid giving law enforcement any more information than they already have. This means exercising your Fifth Amendment right to remain silent, and seeking legal aid if necessary.   

As criminal defense attorneys with over 60 years of combined practice, very rarely have we ever advised a client to consent to a polygraph exam, even under pressure from law enforcement. In most cases, lie detector tests will do more harm than good. At the end of the day, it's always in your best interest to consult with an experienced defense attorney before you take a polygraph exam or make any major decision about your case. 

Contact DuPage County Criminal Defense Attorneys

Most polygraph or lie detector exams take place in the investigative or beginning stage of a case, while police are still in the process of gathering evidence. This stage is a vital point, and every decision you make could be the final straw that breaks your case. Often, the quality of evidence the police obtain during this stage will determine whether an investigation results in a criminal charge or is completely dropped. In these situations, the representation of an experienced criminal defense attorney can offer insurmountable advantages. 

If you or a loved one are involved in a police investigation and are apprehensive about what steps you can take, the dedicated attorneys of Dolci & Weiland can help. With over 60 years of combined legal experience, we know how to protect our clients' interests, whether that's during a tense police investigation or in the heat of a courtroom. To schedule a free consultation or speak with an attorney, contact our office at (630) 261-9098. We are here to help.     

About the Author

Dominick R. Dolci

Managing Partner Dominick R. Dolci focuses his practice on criminal defense litigation and civil litigation. Dom graduated from John Marshall law school in 1990. He began his legal training in the Cook County States Attorneys Office where he worked at 26th and California. He then transferred ...


There are no comments for this post. Be the first and Add your Comment below.

Leave a Comment