IE 11 is not supported. For an optimal experience visit our site on another browser. exclusive report: pentagon to issue lie detectors for u.s. troops in afghanistan's exclusive report ( reveals that the Pentagon will issue hand-held lie detectors to U.S. troops, beginning this month in Afghanistan and then eventually in Iraq. The Army has bought 94 of the $7,500 machines, called the Preliminary Credibility Assessment Screening System, or PCASS. Other branches of the U.S. military have seen the device and may order their own. The total cost of the project to date is estimated at $2.5 million.

In an original story exclusive to, Bill Dedman, a Pulitzer Prize-winning Investigative journalist, reported that the Defense Department says the portable device will save American lives. According to an unclassified memo from the team leader of a U.S. Army detention camp on the outskirts of Baghdad, a portable lie detector at the war front would assist the U.S. Army in discovering who might be involved in militia or insurgent activities. But the lead author of a National Academy of Sciences study of the polygraph says that military men and women will be put at risk by an untested technology.

The new device is a handheld computer with three wires that attach sensors to the fingertips. An interpreter asks a series of 20 questions in Persian or Arabic or Pashto. The operator punches in the yes or no answers on a handheld computer, which reveals the word "Green" if it thinks the person has told the truth, "Red" if it decides the person was deceptive, and "Yellow" if it can't decide.

Polygraph machines have sparked a fierce debate for nearly a century. The scientific community has consistently said that there is little science to show that they work, while the Defense Department still relies heavily on them for security screening. The PCASS device itself is unclassified, and military officials agreed to show it to after the news organization had obtained studies describing the device.

The Pentagon, in a PowerPoint presentation obtained by through a Freedom of Information Act request, says the PCASS is 82 to 90 percent accurate. Those are the only accuracy numbers that were sent up to the chain of command at the Pentagon before the device was approved. However, three Pentagon studies obtained by show a more complicated picture: In calculating its accuracy, the scientists conducting the tests discarded the yellow lights, or inconclusive readings. That brings the accuracy down to 63 to 79 percent, and in conditions far different from those in a battlefield interrogation.

The full story, titled "New anti-terror weapon: Hand-held lie detector," is available at: