Leonarde Keeler

Leonarde Keeler (1903–1949) was the co-inventor of the polygraph. He was named after the polymath Leonardo da Vinci, and preferred to be called as 'Nard.' He was a Berkeley high school student and amateur magician. He was captivated by John Larson’s machine - his so-called 'cardio-pneumo psychogram,' capable of detecting deception, and worked on to produce modern polygraph.

He was born in 1903 in North Berkeley, California. While in high school, he worked for the Berkeley Police Department for the Chief of Police August Vollmer. He was a keen assistant to Larson who had developed a multi-tasking polygraph. After graduating from high school, he enrolled at the University of California, Berkeley in the fall of 1923. He moved shortly after that to enroll in UCLA to follow Vollmer who accepted a new job as the Chief of Police for Los Angeles.

In 1924, Keeler’s first handmade polygraph instrument, which he called "the Emotograph," was destroyed in a fire at his residence. On February 2, 1935, he conducted the first use of his invention, the Keeler Polygraph—otherwise known as the lie detector. Keeler used the lie detector on two criminals in Portage, Wisconsin, who were later convicted of assault when the lie detector results were introduced in court.

One of the earlier uses of the Keeler Polygraph was in 1937, in connection to the murder of 5-year-old Roger William Loomis in Lombard, Illinois. The subject was Grace Yvonne Loomis, the child's mother.

In 1938, Keeler conducted a polygraph test upon Francis Sweeney, the chief suspect in the Cleveland torso murders. Sweeney failed to pass the test, leading many to believe that he was the culprit; however, due to lack of evidence, Sweeney was never charged with the killings.

He above all was most instrumental in the popularization of modern polygraphy in criminal investigation and job screenings. He went as far as appearing in person in the 1948 film noir docudrama, Call Northside 777 with James Stewart, Richard Conte, and Lee J. Cobb, playing himself.

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