H. Michael Steinberg has 38+ years of experience practicing Colorado criminal law. Mr. Steinberg strives to stay current with the ever changing aspects of criminal law issues and updates resulting in his extensive knowledge of successful criminal defense as well as appellate work. He is also an active member of the National Association of Criminal Defense Lawyers, the Colorado Criminal Defense Bar Association, the Colorado Trial Lawyer's Association, and the Colorado and Arapahoe Bar Associations.
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Is an Offer to Take A Polygraph Admissible as Evidence at a Colorado Criminal Trial?

Is an Offer to Take A Polygraph Admissible as Evidence at a Colorado Criminal Trial?By H. Michael Steinberg Colorado Criminal Defense Lawyer

Introduction – The Polygraph Test

I have written about polygraphs in the past but it is a subject that comes up quite often – especially in cases where the evidence against my clients is somewhat weak.

It is not unusual to have a client request a polygraph to prove they are innocent. The question is this – if a defendant takes a polygraph test in Colorado and passes it, is that test admissible at trial, and, if not, is the offer to take a polygraph, admissible at trial?

The short answer may surprise you – that answer is no – to both. The fact that a defendant offers to take a polygraph test and may even have passed that test, is not admissible in a later Colorado criminal trial.

This is a difficult fact to accept for some.

When a person is falsely accused of a crime, that person naturally wants to immediately prove their innocence – to fight the case before charges are filed.  In that context taking a polygraph to prove one’s innocence makes common sense.

This article addresses the dangers of polygraphs during the investigation of a case by Colorado law enforcement and the law in Colorado regarding the admissibility of polygraph evidence.

The Polygraph – What Is It?

A polygraph machine is truly not a “lie detector.”

The polygraph “machine” is essentially a device designed to measure physical reactions within the body that are believed to be impossible to control. It records pulse, breathing, blood pressure, perspiration, and gross motor movements.

The science behind polygraphs is founded on research that supports the proposition that an individual’s responses to both “control” questions and to “test” questions about an investigation – generate physical responses consistent with either telling the truth or lying.

While the science behind the polygraph has made massive advances over the years, almost every court in the country still will not permit the results of a polygraph into evidence at trial.

The idea that expert opinions based upon a subjective analysis of physiological changes in a suspect’s body that are the result of police questioning somehow then enables the polygraph operator to detect if that person is lying or telling the truth…is still just not quite “there.”

The test is, by definition, is “subjective.” Polygraph operators can make errors in interpreting the results. The machine cannot, and does not, account for every individual’s unique composition and psychological reactions. Polygraph “results” are rendered, fundamentally, on formulas that are considered the “average person.”

In addition to technical errors, some polygraphers are better than others at creating the “control” and the “test” questions. The wrong questions can lead to skewed results.  However, notwithstanding these flaws, the polygraph is still viewed as having an “aura of scientific infallibility” and for that reason, the Appellate Courts of Colorado have found that Colorado jurors will give polygraph results significant if not conclusive weight at trial.

Understanding the Role of Polygraphs in the Colorado Criminal Justice System

Polygraph tests are useful tools in the investigation of any criminal case. They are often used as an investigative tool by law enforcement and by defense teams representing the “targets” of certain criminal investigations.

Polygraphs are commonly used:

  • By law enforcement for government security screening, narcotic investigations, insurance fraud, and other corruption cases, child abuse cases, and missing person cases.
  • By private investigators who perform pre-employment screening, and
  • By defense lawyers to attempt to clear the wrongfully accused.

How Polygraphs are Used to “Trick” Persons Under Investigation to Make Mistakes

First, it is critical to understand that the accused is NOT required to prove their innocence. The Government has the bruden of proving the guilt of the accused, beyond a reasonable doubt!

A common tactic used by law enforcement is to try to convince you that refusing to take a polygraph is an admission of guilt.  They use an old tactic which suggests that an innocent person would never refuse a polygraph test that could prove their innocence,

Know this, the police and the prosecutor (if involved in the case) already believe the target is guilty … they just need to prove it.

Most of the time, neither the police nor the District Attorney really care about the result of the “poly.” The goal is to somehow cause the suspect to “slip up” and say something that can be used in the prosecution of the case to make a weak case much stronger.

It is an old tactic used by law enforcement to find a way to prevent the early exercise of a suspect’s constitutional right to remain silent and the right to seek the counsel and protections provided by an experienced criminal defense lawyer.

Those on the prosecution side (I was an Arapahoe – Douglas County Colorado career prosecutor for over 13 years)  – know that actually refusing a polygraph is not interpreted by the police one way or the other. They already believe you are guilty.

Even if there is a “no deception” result at the end of a voluntary polygraph, the police are legally allowed to lie to you, for example by telling you that you failed the poly. Remember this, the goal of the poly procedure itself is to cause a suspect to “slip up” and to make an admission of fact that can later be used to strengthen the government’s case.

Almost nothing is out of bounds.

In Colorado, as explained below, the results of a polygraph test, …pass, fail or inconclusive, … are not admissible at trial. But there can still be, sometimes, good reasons to take a polygraph. But the decision to seek a polygraph should never be made without consulting an experienced Colorado criminal defense lawyer.

There clearly are times when a polygraph, privately administered or provided by a law enforcement agency, makes good sense. Taking a polygraph can be a sound tactical move intended by an experienced criminal defense lawyer to persuade law enforcement to “look elsewhere” for a new suspect. However, in most cases, taking a polygraph test, even when a person is innocent, is rife with danger in ways that are unpredictable to an unrepresented suspect in a serious criminal case.

Example – A Typical Investigation: The Use of a Polygraph in a Colorado Sex Crime Investigation to Obtain Evidence Against a Suspect

Here is a typical scenario of how law enforcement will use the offer of a polygraph as a tool for obtaining useful evidence against a suspect. This case uses as an example a Colorado sex crime case investigation.

Let’s assume a Colorado County Sheriff’s Department is investigating allegations made by a woman that she has been sexually assaulted by the defendant in a “date rape” type scenario.

The case is weak and with no forensic evidence and no eyewitnesses.

A sergeant with the Sheriff’s Department recognizes these weaknesses and has contacted the unrepresented target, the suspect, and has gained his consent to take the polygraph. He has arranged to meet with the suspect at the Sheriff’s Department for the test.

At the Sheriff’s Department, the sergeant informs the defendant that he is a suspect in a sexual assault case and that the sexual assault occurred the week before the meeting.

The Time-Line

I. The Pre-Poly “Interview”

The Sergeant advises the suspect of his Miranda rights, which he waives.

During the interview, the goal of the police is to obtain either a full confession or statements that can later be used at trial against the suspect.  If the suspect still refuses to admit anything useful to law enforcement, the “ruse” proceeds to the next stage.

At the close of the “pre-interview” the Sergeant asks the suspect if he would now be willing to take a polygraph examination – sometimes promising that if he passes the polygraph test, the police will not proceed further in their investigation. The suspect agrees to take the poly.

II. The Polygraph

The polygraph is taken by a “polygraph technician” employed by the Sheriff’s Department. The suspect signs a written consent form which includes another Miranda advisement.

Using the pretest interview and other research from the investigation, questions have been crafted by the polygrapher in an attempt to trip up the suspect. After administering the polygraph test, the polygraph technician reaches the conclusion either that the suspect did not tell the truth (deceptive), that the suspect passed the poly, or that his answers were “inconclusive.”

No matter what the result, the polygraph technician typically then informs the suspect that he still does not believe “his story” and the procedure goes to the next stage – the post polygraph interview.

III. The Post-Polygraph Interview

No matter what the result, pass or fail, the accused will be asked to “explain why his test came out the way it did.” The hope here is that the accused will then “spill the beans” and admit the crime under investigation or at least make some statement against interest.

At trial, while the results of the polygraph are NOT admissible, the District Attorney is permitted to identify the polygraph operator as a “police investigator” and he or she is usually allowed to testify to the pre and post polygraph statements made by the defendant.

So What SHOULD You Do? Take a Polygraph or Not?

In order to make a wise decision on the issue of taking a polygraph during a criminal investigation, your criminal defense lawyer, who is tasked to protect your best interests, must know all sides of the present state of the investigation before counseling on the decision to take or to refuse the test.

Until this determination can be made, the only advice that makes sense is to invoke the right to remain silent and refuse the polygraph test. Asking for a lawyer – also called “lawyering up”– instructs the police, DA investigators, and prosecutors as well, to stop all communications with you relevant to the investigation ending all questioning.

It is also clear that the tactical use of a polygraph if fully accepted by law enforcement as conclusive, can free the falsely accused of suspicion, especially if there are other facts and circumstances that lend credence to a non-deceptive result of the polygraph which may establish that the accused did not commit the crime under investigation.

The Question: What is the Law in Colorado Regarding the Presentation of Polygraph Evidence at a Criminal Trial?

Lie detector tests, at least in Colorado, are not admissible as evidence at trial – full stop. They have been found not to have enough reliability to justify the admission of the test results through the required expert testimony. The courts have held that polygraphs usurp the province of the jury as the fact-finder of truth.

As you will read below, it follows then that an offer of a suspect’s willingness or unwillingness to take such a test is likewise not admissible at trial.

The reasons make sense.

Under Colorado law, the relevant rules of evidence –  Colorado Rule of Evidence (CRE) 403 and 702, govern the admissibility of polygraph evidence. Under those rules, it has been held that polygraph evidence is “insufficiently reliable” under CRE 702 and “unduly prejudicial” under CRE 403 because polygraph evidence could influence the jury and usurp the jury’s role of determining the credibility of witnesses.

The introduction of evidence that “invades the province of the jury” directly infringes on the authority of the jury and can unduly influence its decision regarding witness credibility.

Furthermore, the courts have found that because of the unreliability of the “polygraph technique” and the lack of consistent qualification standards for examiners, “there is a serious risk that the admission of polygraph evidence at trial would unfairly prejudice and mislead the jury” and that “there is an inherent danger that a jury will rely too heavily on the results of a polygraph test.”

A jury’s duty and responsibility is to collectively “find the facts” and to determine whether the defendant’s guilt has been proven beyond a reasonable doubt. The fear is that that responsibility would be prejudiced by the admission of polygraph evidence.

The Question: What is the Law in Colorado Regarding the Presentation of Polygraph Evidence at a Criminal Trial Where the Defendant Offers to Take a Polygraph?

In the 1990 Colorado case of People v. District Court, 785 P.2d 141 (1990) the tables were turned. The question, in this case, was whether the exclusion of evidence that the defendant actually offered to take a polygraph examination at the investigation phase of the case was the correct ruling at trial.

The answer was yes, such an offer to take a polygraph is also not admissible in evidence.

In this case, the defendant argued that his offer to take a polygraph examination should be admissible because of the commonly held belief that because law enforcement authorities consider such tests to be reliable and that guilty defendants are therefore unlikely to volunteer to take such a test.

He argued that evidence that a defendant who has offered to voluntarily take a poly, presents a kind of  “consciousness of innocence,” and should therefore be admitted into evidence at trial. People v. District Court 785 P.2d 141 (1990)

In this case, the defendant had offered to take a “lie detector test” during an interview of the defendant during the investigation.

The court, in this case, concluded that “as a matter of law” evidence of a defendant’s offer or willingness to take a polygraph examination is irrelevant to show consciousness of innocence.

In the court’s review of other states, it found that the majority of those states have held that evidence of a defendant’s or a witness’s offer or willingness to take a polygraph examination is inadmissible to show consciousness of innocence or in the case of a witness, to bolster the credibility of that witness.

The Court held that admitting this kind of evidence “would create a substantial danger of confusing the issues and misleading the jury.”

People v. District Court 785 P.2d 141 (1990)

In the words of the Court:

A fact finder’s assessment of a suspect’s offer to take a polygraph test would require consideration of the suspect’s subjective state of mind;

subjective beliefs of particular law enforcement officers as to the value of such a test under the circumstances;

evidence of the behavior and beliefs of hypothetical “reasonable” suspects and officers in the circumstances of the case (to test the expressed subjective beliefs of testifying defendants and officers);


if a test were not conducted, hypothetical scenarios concerning what officers would have done with the test results in the event the defendant “passed” or “failed” the test.

People v. District Court 785 P.2d 141 (1990)

Summary and Conclusion – Is an Offer to Take A Polygraph Is That Evidence Admissible at a Colorado Criminal Trial?

The reader should not conclude from this article, which addresses the admission of polygraph related evidence at trial in Colorado, that polygraphs are not useful in a comprehensive defense strategy for other reasons than the admission of that evidence at trial.

I have used polygraphs to steer law-enforcement away from my clients at the pre-filing investigation phase of a Colorado criminal case. Polygraphs are widely used as an investigative tool by law enforcement, including the primary decision-maker as to whether charges are filed or not, the District Attorney. Colorado prosecutors will sometimes agree to rely on the results of a polygraph in making the decision NOT to ultimately file charges.

Never stop fighting – never stop believing in yourself and your right to due process of law.

H. Michael Steinberg Colorado Criminal Defense LawyerABOUT THE AUTHOR: H. Michael Steinberg – Email The Author at hmsteinberg@hotmail.com – A Denver Colorado Criminal Defense Lawyer – or call his office at 303-627-7777 during business hours – or call his cell if you cannot wait and need his immediate assistance – 720-220-2277. Attorney H. Michael Steinberg is passionate about criminal defense. His extensive knowledge of Colorado Criminal Law and his 38 plus years of experience in the courtrooms of Colorado may give him the edge you need to properly defend your case.