Pittsburgh Post-Gazette staff writer Michael A. Fuoco reports. Excerpt:
To tell the truth, polygraph examiners for Pittsburgh and Allegheny County police didn’t blink an eye last week when a National Research Council study found that lie detector tests administered annually to tens of thousands of federal employees hadn’t uncovered a single spy.
But the local detectives’ lack of surprise at the findings doesn’t mean they doubt the effectiveness of polygraph examinations especially in criminal investigations. And they say the study illustrates how important an examiner is to the process of getting a valid result.
Polygraph examinations are effective tools in criminal investigations because examiners are able to formulate questions relating to a specific known crime, said the two local experts: homicide Detective George Satler and Allegheny County Police Sgt. Bob Downey. Satler is one of one of the city Police Bureau’s three polygraph examiners and Downey is a certified examiner who heads the county’s general investigations squad.
On the contrary, using them to screen for spies is a tough, if not impossible, task, because the general nature of the probe doesn’t permit an examiner to, as is imperative, focus his questioning on a specific incident.
“I wouldn’t know how to formulate questions to polygraph for that,” Satler said. “That is so much different than what we do.”
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Pittsburgh, Allegheny County and other law enforcement agencies conducting criminal investigations, generally speaking, use polygraph examinations only after a field of suspects for a specific crime has been narrowed to a few people. The city also uses them when convicts or suspects in crimes want to “snitch” on another person. Assistant Chief William Mullen, who heads the investigations branch, said such informants are not used as court witnesses unless they pass the exams.
In criminal cases, the voluntary polygraph tests are effective because they can eliminate from the suspect pool those who pass them, freeing detectives from chasing dead ends. Conversely, if someone, in police terminology, “bombs the box,” meaning was found to be deceptive, detectives can focus more on that person.
But police don’t see polygraph machines, which measure variations in heart rate, blood pressure, breathing rate and galvanic skin response (a body’s electrical impulses), as a be-all, end-all. Far from it.
In fact, of the more than 2,300 cases the county’s detective division investigates in an average year, polygraph examinations are used in about 75 of them. An average of another 55 examinations are conducted for municipal departments.
“A polygraph examination is not a starting point [of an investigation], it’s an ending point,” said Downey, who, as a supervisor, no longer conducts the examinations but oversees the county’s two examiners, general investigations Detectives Ed Adams and Ed Fisher.