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Sunday, October 13, 2002

By Michael A. Fuoco, Post-Gazette Staff Writer

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.

	The metal rods of a polygraph machine record a subject's variations in heart rate, blood pressure and breathing rate, as well as the body's electrical impulses. (John Heller, Post-Gazette)

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."

The two-year study for the National Research Council, an arm of the National Academy of Sciences, was headed by Stephen Fienberg, a Carnegie Mellon University statistician. He reported that when used as a screening tool, polygraphs can be expected to miss many, if not most, spies, while misidentifying untold numbers of loyal citizens as suspicious. The use of polygraphs by federal agencies to screen out security risks has grown since the Wen Ho Lee "spy" case at Los Alamos National Laboratory.

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.

"It's a tool. All it is is a tool," Mullen said. "Good interrogators are the key and very, very good ones are hard to find."

Generally speaking, polygraph examinations are conducted as follows:

In most cases, the polygraph examiner is not the investigator on the case, so he or she must first familiarize himself with the case at hand.

Next comes the pretest interview with the suspect, both to establish a rapport and to gain some background and psychological information. That process takes about an hour.

Then the examiner makes certain he's focusing on the right issues and formulates his questions, including some control questions to establish a baseline, and others specifically relating to the crime being investigated. The examination also takes about an hour.

The examiner then interprets the results and determines if the suspect is being deceptive or truthful. Sometimes the results are inconclusive.

Next comes the post-test interview, during which the suspect is told of the results. Even if the result is "truthful," the interview is conducted so the examiner can be as certain as possible he didn't miss something in his question formulation. If the result is "deceptive," the interrogator will lay out the case for the suspect and explain why they are focusing on him or her. Oftentimes, faced with a deceptive result on the test, a suspect will confess.

That raises the question: If a suspect is guilty, why would he volunteer to take a polygraph?

"A lot of times it's arrogance," Downey said, "and a lot of times they've heard there are ways to beat a polygraph by trying countermeasures such as changing breathing patterns or moving during certain questions. But to an examiner those are all indicative of deception."

Satler said some people try techniques involving pain -- a tack in their foot or biting their lip -- in an attempt to throw off the testing. It doesn't work, he said.

"The reaction is so extreme it tells an examiner the suspect is trying to manipulate the test and the only reason you would try to manipulate it is because you're guilty," he said.

Satler said some studies had put the reliability of polygraph tests at between 96 and 98 percent, but, he said, examiners, who take a two-month course to be certified, are taught that when deciphering results that could go either way, to lean toward a person's telling the truth rather than their being evasive.

Neither sees anything on the horizon replacing the investigative tool for use in criminal probes, but as for effectively screening for spies, they don't have a clue of how a polygraph can accomplish that.