Xerox Brand Lie Detector
Bucks County Police Department detectives were faced with a problem -- they had a suspect in custody that they just knew was guilty of a serious crime, but they couldn't get a straight answer out of him and the district attorney had been frowning on the old "hot lights and rubber hoses" routine for the last couple of decades.
But instead of giving up, they used the tools they had at hand and converted the department's copy machine into a lie detector.
First, the detectives wrote "It's a lie" on a piece of paper and placed it into the machine. Then they put a metal colander from the department kitchen on the suspect's head and connected it to the copy machine with their shoelaces.
With the device ready, the interrogation began. Every time the suspect gave an answer the detectives didn't believe, they pushed the button on the machine and out came a paper that said, "It's a lie." Seeing that deception was fruitless, the suspect gave in and confessed.
When the case came to court, the detectives revealed their method of extracting a confession. The judge, after hearing the whole story, was laughing so hard that he accidentally knocked the suspect off of the witness stand, and the suspect fell to the courtroom floor and broke his arm.
In some versions of this story, the events take place in Radnor, Pa. and "copy machine" is replaced with "Xerox brand document reproduction device."
Behind the Legend
The example cited above is a fairly accurate account of an incident that occurred in 1962. Other police departments have used this method (with greater or lesser success), and it was immortalized on an episode of the original Dragnet television show, with a stern Friday asking the questions and a smirking Gannon operating the copy machine.
The principle of using an impromptu "lie detector" to get information, however, goes back much further.
In 1775 in what would become the United States, the rebels captured a man they believed to be a British spy. The man stuck with his cover story and seemed impervious to questioning. Unsure of what to do, the rebels brought the prisoner to Benjamin Franklin.
Franklin came up with the idea of setting the words "In truth, it is a lie" in type on a printing press and having the prisoner place a hand on the side of his "new invention." Every time the prisoner said something that was suspected of being a lie, Franklin operated the press and showed the resulting piece of damning paper. The prisoner, amazed by Franklin's device, quickly broke down.
There is a tradition that, had this failed, Franklin would have attached a sensitive part of the prisoners anatomy to the string of a kite during a lightning storm, but this tale is out of character for Franklin and likely false.