The polygraphist uses polygraphy (science of verification of the truth based on psychophysiological analogues) to assist SPVM investigators in seeking perpetrators of crimes and evidence in order to solve crimes committed.

Thus, with the assistance of specialized tools made available to him and his expertise, the polygraphist administers the polygraph test to obtain confessions of guilt, exoneration of innocent suspects, corroboration of information received from inform providers or informants, or detection of omissions, dissimulations or lies in the statements of victims, witnesses or suspects. In addition, he provides a technical interpretation of the results of the polygraph charts.