The evidentiary value of polygraph is found in the statements made by the individual tested and in testimony regarding these statements that is permitted by the courts. Polygraph assists investigators and Commonwealth Attorneys in eliminating or isolating suspects in any criminal felony case. It is also of value to the Commonwealth Attorneys in negotiating plea agreements which in turn frees officers and analysts from time spent in court and saves the cost of a court trial.
Polygraph is useful in determining whether a person is a viable suspect of a reported crime.
It eliminates possible suspects which in turn saves investigative time and effort. It is useful in determining the degree of involvement of suspect in the crime, i.e., coconspirator, accessory before or after the fact, or the violator himself. By admissions or confessions made by the individual being tested, direct involvement can be established which often leads to a plea. Admissions made by the individual being tested can establish involvement in other or unreported crimes. By videotaping the test and interview, the tape may become useful to the Commonwealth Attorney in developing an approach to the person during testimony in court.