Polygraph Testing Use in Sex Crime Cases

Police sometimes use polygraph testing, also known as a “lie detector” test, in criminal investigations. The use of polygraph tests remains highly controversial, and states vary widely in their rules regarding the admissibility of polygraph results at trial. A defendant may retain a private company to perform a polygraph test in order to raise doubts about the state’s evidence. A Washington sex crimes defense attorney with knowledge of polygraph procedures and rules can help prepare you for a test, challenge the validity or admissibility of the state’s results, or retain a testing company to conduct a separate test.

What is a Polygraph?

A polygraph machine measures and records a test subject’s physiological responses, such as pulse rate, breathing, and blood pressure, to questioning by a test administrator. The theory is that a person will display different physiological responses when giving deceptive answers than when answering questions truthfully. The scientific community generally does not consider polygraph testing to be reliable. The nature, or even the tone, of the test administrator’s questions can affect the test results, along with factors like the stress of submitting to a police “lie detector” test in the first place.

Use of Polygraph Testing in Sex Crime Prosecutions

Because of the subjectivity and questionable reliability of polygraph testing, the admissibility of polygraph evidence in court is subject to strict limits. This includes the agreement of both sides to both the defendant’s participation in the test and the admissibility of the results. State v. Renfro, 96 Wn.2d 902, 906-07 (1982).

Use of Polygraph Testing in Sex Crime Investigations

Law enforcement in Washington may still use polygraph testing in the early stages of an investigation, including an investigation into alleged sex crimes. A magistrate judge may consider polygraph evidence, for example, in making a determination on probable cause for a warrant. State v. Clark, 24 P.3d 1006, 1015 (Wash. 2001). Washington law prohibits police from asking or requiring an alleged sex crime victim to submit to a polygraph test, but it does not prohibit them from using a voluntary test in an investigation.

Use of Polygraph Testing in Sex Offender Registration

Polygraph testing plays a role in the management of sex offender registration and the treatment of “sexually violent predators.” A court may take polygraph results into consideration in granting relief from the duty to register, or granting conditional release to individuals ordered into mental health treatment.

Defending Against a Sex Crime Charge with Polygraph Testing

Police polygraph testing is more like an interrogation than an objective test. The goal of such a test is to examine the specific elements the police must prove to establish guilt. A defendant can retain a private polygraph testing company to perform a test that is far more fair to the defendant’s interests. Test results may be no more admissible in court than the police’s test results, but they may effectively counter those results or serve as a basis for excluding other evidence.

Individuals have constitutionally-guaranteed rights during all stages of a criminal case, including the right to confront witnesses and review evidence against them. You should seek the assistance of an experienced Washington criminal defense lawyer to protect yourself against possible abuses by state officials, including police, prosecutors, and judges. Vindicate Criminal Law Group has defended people in sex crimes cases in Vancouver, Kirkland, and the western Washington area since 1995. We have successfully challenged the state’s evidence in many cases, resulting in reduced sentences, probation, other deferred dispositions, acquittals after trial, and outright dismissals. To schedule a confidential case evaluation with a member of our team, contact us today online or at (888)-212-4824.