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What is a polygraph test?

A polygraph is a three-part test that measures various physiological processes that can indicate whether a person is telling the truth about an event, experience, or past action.

Can a person beat a polygraph test?

There are ways to mess with the test, but they’re all observable. If a person tries to alter the test, they generally get a warning from the examiner. If the person continues, the test stops and is deceptive by virtue of countermeasures. Countermeasures are methods the investigators use to detect when the person is trying to alter the results of the lie detector.

Trimarco notes, "It's very, very difficult for a person with no polygraph background to sit down and mislead a former federal examiner or someone who has an education in countermeasures."

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Why would I need/take a lie detector test?

Polygraph testing isn’t just for criminal investigations. There are many situations in which you can ask or be asked to take a polygraph test.

Background checks

Marital issues

Family issues

Employee theft

Pre-employment testing

FBI, CIA, or police application

Customs and border protection

How does a polygraph work?

The examination is administered by a trained investigator and can take up to two or three hours, possibly more depending on the scenario. It is comprised of three parts:

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Part 1: The Pre-Test

The pre-test is a conversational interview during which the examiner makes a judgment as to whether the person is capable of being polygraphed. The examiner will ask questions involving the person’s amount of sleep, medication use, drug use, and mental psychopathy.

"I need them to have a grasp of reality at the time of the event and in the polygraph exam room," expert polygraph examiner Jack Trimarco says. "It's an evaluation to be sure that this person can receive a polygraph test that is going to be valid."

Part 2: The Test

During the test portion, a physiological recorder measures three bodily indicators that reveal when a person lies:


Heart Rate/Blood Pressure

Cardiovascular activity is measured by a blood pressure cuff.


Breathing patterns are captured by pneumographs wrapped around the subject’s chest.

Skin Conductivity/Perspiration

Perspiration is documented via electrodes attached to the fingertips.


While the polygraph measures reactions, the examiner will ask a series of questions. Sometimes, the same question will be asked multiple times in the search for a consistent significant reaction or lack thereof. The questions include control questions that set a base for relevant questions, which are directly related to the reasons for taking the polygraph. In theory, a truthful person will react more significantly to the control questions than the relevant questions.


Note: A polygraph measures what a person believes to be the truth, not necessarily what actually happened.​

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Part 3: The Post-Test


Once the test is complete, examiners measure the reactions and come to one of three possible


  1. Telling the truth

  2. Not telling the truth

  3. No opinion


What does a "no opinion" result mean?


No opinion, formerly referred to as inconclusive, means that the investigator could not determine whether or not the person was telling the truth. About 10% of lie detector tests result in no opinion.

How accurate is a polygraph?


The accuracy of polygraph testing is a highly debated subject mostly because human reactions are not standardized. An honest person may act nervous while a deceptive person might maintain calm. There’s also little research that examines whether outside factors, like education or intelligence level, affect the test.

We also provide polygraph testing for:

Law enforcement applicants

The public and business

Attorney and their clients

TV / Media / Film Productions


Sex Offenders

Natural Bodybuilding Events






Meet Our Polygraph Examiner


Fernando Fernández


Fernando Fernández is a licensed private investigator with a proven 19-year track record of solving cases internationally. 

He is a professional polygraph examiner recognized by Polygraph Examiners of America & American Polygraph Academy. He has established himself as a trusted authority in truth verification.

Fernando has conducted polygraph tests for a diverse clientele, ranging from individuals seeking truth in personal matters to private corporations and government agencies. Confirm by his colleagues, his commitment to the highest standards of ethics and accuracy has earned him a reputation as the best polygraph examiner in the Caribbean region.

As he skillfully utilizes his background as a specialist in body language and micro expressions. Prior to subjecting individuals to polygraph examinations, he employs his understanding of non-verbal language to analyze interviewees. This approach enhances the overall effectiveness of the polygraph tests he administers, elevating the precision and reliability of the results. 

Throughout his career, Fernando has become a sought-after figure in the field, known not only for his technical proficiency but also for his dedication to ensuring justice and truth prevail. His commitment to the art and science of polygraphy, coupled with his astute grasp of human behavior, continues to make him a formidable force in the world of certified polygraph examination and private investigation.

Some of the noteworthy cases conducted by the polygraph examiner include:

  • A polygraph tests for over 50 police cadets from various municipalities in Puerto Rico, contributing to ensuring the integrity and trustworthiness of the police force.

  • Successfully administered a polygraph test related to a case of child abuse, prompting the examinee to confess the actions. His expertise proved crucial in obtaining vital information for the investigation.

  • Presented his testimony in court for a case where the client was accused of abusing a minor and decided to take a test to prove his innocence. Fernando's testimony and the test results played a decisive role in the legal proceedings.

  • Conducted polygraph tests for several doctors who did not pass the revalidation exam, providing objective data on their performance. This assessment contributed to maintaining high standards in medical practice and ensuring the competence of healthcare professionals.

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