February 2, 1935 Leonarde Keeler, co-inventor of the polygraph machine, first uses his invention. 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. First Polygraph Used is original content of This Day in Tech History. This Day in Tech History…

February 2, 1935 Leonarde Keeler, co-inventor of the polygraph machine, first uses his invention. 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. First Polygraph Used is original content of This Day in Tech History. This Day in Tech History…