News & Features » News and Features

Truth Seeker

Go ahead, make his day. Detective Karl Holzbach knows when you're lying.


The room, like the hallway, is sterile blue and feels like a hospital. It's brutally silent, except for the whir of an air conditioner. Holzbach points to a chair in the corner and sits at a computer desk parallel to the chair. This chair looks like any other office chair. But it isn't. Sensors in the back, on the seat and on the floor's foot pedals will tell Holzbach when you're shifting around to avoid the question … or to lie.

The Richmond City Police Department isn't shy about using its polygraph — or lie detector — on anyone from potential perpetrators to potential police. It feels like an episode of "Perry Mason." But there is no machine with twitching needles that move along a scroll of paper like a seismograph. Interrogation has gone digital, and it all fits into a small computerized box about the size of a computer battery.

"We have a saying, 'In God we trust, all others we polygraph,'" says Holzbach, who has conducted more than 1,400 polygraphs for city police.

It's not just for catching bad guys. New police recruits face an hour-long interview and an additional hour-long polygraph test.

Among the 53 pre-employment questions he asks all potential officers are those that involve drug use, felony convictions and sex with minors. If the interview doesn't go well, there's no second chance. Holzbach will see to it.

The demand for his little black box is growing. Currently, there's a two-week waiting list for pre-employment polygraphs. And the backlog has grown so much that Richmond police are in the process of hiring two additional polygraphers.

While the technology has gotten more sophisticated, the techniques polygraphers use to catch criminals have remained relatively unchanged.

And so, too, has the long-standing controversy. With the advent of more sophisticated evidence-gathering techniques, such as DNA testing, the polygraph has been summarily dismissed by the criminal justice system. Critics say the polygraph is unreliable and inconsistent, and the courts have agreed.

"The only thing a lie detector can do reliably is [show] physiological responses," says Steven Benjamin, a local lawyer at Benjamin & DesPortes. "I do not think it is a reliable tool for detecting deception." He says polygraph tests are not admissible in court and that they are used more as tools of intimidation than as truth detectors.

Hogwash, says Holzbach. While the judges may not admit polygraph tests as evidence in a court of law, the machines contribute in other ways that assist in police investigations and often prove to be extremely valuable, such as locating the body of a murder victim.

"I ask questions like: 'Is she buried in the ground? Is her body in the trunk of a car? Is her body in a pond?'" he asks rhetorically. How the suspect responds can tell police where to start looking for the body.

And it can help vindicate those who are innocent, he says.

Holzbach remembers one case where a robbery suspect was accused by three already convicted robbers. He faced 15 felony warrants. The suspect was given two polygraph tests and passed both, Holzbach says.

"He wasn't no saint by any means, but he hadn't done those robberies," he says. The man was let go. "To this day, there's no doubt in my mind that he didn't do those robberies," says Holzbach. "This is a great tool to vindicate people who are innocent."

But how does he know? A good polygrapher knows all the tricks, says Holzbach.

"You can go on the Internet and look up [ways] to beat the polygraph," says Holzbach. He visits those sites too. "I go to them all the time because I can't wait to see what the next knucklehead comes up with."

Web sites devoted to passing polygraphs suggest interviewees flex their butt cheeks to throw off seat sensors or put tacks in their shoes — the pain is distracting enough, the theory goes, that it takes their mind off the test. When Holzbach catches someone cheating, he stops the test and gives the interviewee a talking to.

"I read these things all the time. I know what they are up to," he says. "I give them the benefit of the doubt. Then we start the test again."

Holzbach interviews everyone from witnesses to murderers, from potential police officers to potential perpetrators. Most of the people who try to beat the polygraph are trying to become policemen, he says. When he catches them, he stops the test and shows them the door.

It works, says Holzbach. On the eve of convicted murderer Roger Coleman's execution in 1992, he was given a polygraph test and the chance to prove his innocence. Then-Gov. Douglas Wilder faced intense public pressure to pardon Coleman. Everyone from the pope to Mother Teresa called pleading his innocence. Coleman failed the polygraph exam and critics cried foul. A man executed because of a failed polygraph.

Fourteen years later, Holzbach says, Gov. Mark Warner allowed Coleman's DNA to be sent to a lab in Canada for testing. It was a match. Coleman was guilty, after all.

The DNA evidence proved that the polygraph is a reliable tool for extracting the truth, Holzbach says, and it vindicated of the validity of the polygraph.

Still, not everyone concurs. The Coleman case is a shameful example because the police had agreed to let his lawyers watch the examination and then reneged on their offer, Benjamin says. Then the police destroyed the polygraph charts.

"The police acted as if they had something to hide," he says. Others say there is more that could be done to improve the lie-detecting technology.

"Polygraphing is sort of the gold standard of detecting deception," says Feroze Mohamed, assistant director of Temple University's Functional Brain Imaging Center. "The polygraph, in the best hands, has an accuracy of 90 percent. [This] drops down to 70 percent when someone is not guilty." The polygraph can be manipulated because it measures only the end result, he says.

An associate professor of radiology at Temple, Mohamed is currently studying the uses of functional cognitive brain patterns as an alternative to the polygraph. His research measures brain waves while someone is lying or telling the truth. This technology is available now, he says, but needs fine-tuning before it's used by law enforcement.

"Because of the nature of how the polygraph is obtained, we can cheat the system," he says. "By when you talk about brain imaging, it's harder to cheat the system."

Mohamed doesn't think police should give too much credence to polygraph tests.

Benjamin agrees.

"It's my belief that all we will be able to do is detect responses [with the polygraph], but not whether they are lying," he says.

Although Holzbach says he believes in the accuracy of the polygraph, he also says that this test is not a substitute for an investigation.

"Don't think for a second that the polygraph saves the world," says Holzbach. He says he knows the criticism but still believes in the benefits of using it.

"I think it's looked at negatively because it's looked at to catch someone in a lie," he says. "But it's really made for the innocent person. It has helped to clear people, too." S

Add a comment