One of the more frequent questions criminal lawyers have to field is about the accuracy and admissibility of the polygraph, commonly known as the lie detector machine.
The myth that seems to hang on is that this device gets the lowdown on the truth and that if only an individual or a client takes the test and passes it, all criminal charges against them will suddenly disappear – the police and the Prosecuting Attorneys will see the error of their ways and that will be the end of it.
Results of a Polygraph Test Are Not Admissible
Alas, such is not the case. The results of a polygraph test are not admissible in evidence in a court of law, but to the confusion of many, some police and insurance agencies are fond of suggesting it in order to exonerate a suspect. It always sounds totally tempting to an innocent individual who feels the results of the test can only help him or her in all circumstances. Not so, my dear readers, stay tuned for the real scoop.
Of course, as members of The Criminal Law Team, our main focus is the protection of our clients from criminal liability, so let`s establish a few key points to set the record straight.
First, the courts have effectively ruled that the results of lie detector tests are little more than junk science or looking at it another way, the scientific evidence is not available at this point in time to satisfy the courts that the test is reliable enough to allow a machine to replace the function of a judge or jury, that is to decide the question of guilt or innocence.
Any Statements Made In The Course of the Polygraph Can Be Used Against You!
Secondly, and more importantly from criminal defence counsel`s point of view, any statements made in the course of providing answers during the test can be used against the person suspected of committing a criminal offence, whether it be a crime of violence such as assault, robbery, dangerous driving, sexual assault, arson or murder, or some non-violent offences such as fraud and theft from an employer. This is true whether you register a pass or fail in circumstances where the boys and girls in blue decide that your statement helps support some other piece of evidence they might have against you – evidence you may not have known even existed, such as a false accusation made by someone who had something to gain by cooperating with the police.
And, just to extend the caution even further, the operation of the polygraph is far from an exact science and the result, being a pass or fail on the crucial issue of guilt or innocence is based on a subjective interpretation of the data, which may be biased because of the examiner’s previously held beliefs.
The Bottom Line
The Criminal Law Team strongly suggests that you contact competent and experienced criminal law professionals before you decide to make any statement to an investigator from the police, or any other agency; and this, of course, includes taking the lie detector test itself.