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How Do I Get a Lie Detector Test Done?

Private investigators have identified lie detectors as important tools in establishing the truth in many challenging situations. Whenever there is suspicion of a crime, the most reliable proof for private investigators is some form of evidence. Unfortunately, the evidence isn't always available when the private detectives need it. This can make it hard for the private investigator to get to the truth.

Luckily, a tool that has been used by private investigators for years can help in such situations. The lie detector, which has been around in various forms for almost a century offers a means through which the truth can be established by the private eye.


How Is A Private Investigator Lie Detector Test Conducted?

There are several ways that a private investigator can conduct a lie detector test. The two most commonly used methods are the:

  • Control Question Technique
  • Guilty Knowledge Test

In the control question technique, the private investigator starts by performing an interview to provide certain basic details. These details will be used by the private detective to develop some of the diagnostic questions the subject will be asked. The private eye will also explain how the test works, emphasizing the need to answer questions honestly.

The actual test requires the private investigator to ask the subject a series of questions.

There are three types of questions that are asked by the private investigator conducting the test:

  • Irrelevant questions
  • Diagnostic questions
  • Relevant questions

Although the relevant questions are the ones with the most significance to the case, diagnostic and irrelevant questions also help in forming a baseline so the investigator can know what kind of response to expect when the subject is telling a lie and what to expect when they're telling the truth. The guilty knowledge test is conducted a little differently by private investigators.

This test checks how the subject responds to information that only the guilty party would know. For example, the investigator can ask how much money was stolen and give the subject a number of choices to choose from.

It's not the response of the subject that is of significance to private investigators but how they react when they hear the information that is relevant. For example, if the amount missing was $10,000, the suspect is likely to exhibit a stronger reaction when they hear this value. This only works if this information is not already common knowledge.


Who Conducts The Lie Detector Test?

Lie detector tests are usually conducted by professional private investigators. There are several reasons why it's necessary for a professional private detective to do this.

For starters, the private investigator not only uses the information from the lie detector to know if you're lying, they may also want to see your live reactions. This is because some subjects use certain methods that can interfere with the responses registered by the machine.

Private detectives also have no bias in the case. Someone who is involved in the case in one way or another can intentionally or unintentionally influence the responses of the subject.

It's also necessary for the private investigator to carry out the test with professionalism. Investigators who methods that make the subject afraid or nervous can result in strong stress responses even in innocent people.

In the case of the guilty knowledge test, some private investigators work in teams, where the party asking the questions has no knowledge of which choice is the correct one. This prevents them from unwittingly influencing the subject's responses.


How Long Does A Private Investigator Lie Detector Test Take?

If there is only one person being tested, it can take a private investigator anywhere from a few hours to a whole day depending on certain factors. Setting up the equipment and the room where the testing is going to be done will take some time. The private investigator will also have to take their time with the questions to ensure that they're asking the correct questions and providing enough time to register a response from the subject of the case. If there are many persons to be tested, it can take a private investigator a day or even longer since preparations and testing need to be done for each one.



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