Polygraph services are mostly utilized once an incident has occurred. The polygraph test is there to both prove the innocence of the “not guilty” and the guilt of any perpetrators. Polygraph tests are quick and efficient and can eliminate the need for lengthy investigative processes. It is important to remember, however, that no one is legally obliged to undergo a polygraph test, but that reluctance to take one can arouse suspicion as to the reasons for declining.