private polygraph consultant. Personal life Keeler was the son of author and naturalist Charles Keeler. He married a fellow psychology student Katherine (Kay) Applegate in 1930 in Chicago. She was trained as a forensic sleuth, becoming the nation’s first female handwriting analyst. Later on, she established her own all-woman’s detective agency in Chicago, specializing in forensic investigation, and left Keeler to marry another man, Rene Dussaq, and during World War II joined the WASPS (Women’s Auxiliary Service Pilots). She died in 1944 near Patterson Field in Ohio while flying solo across the country to help halt the disbanding of the WASPs. Later life and death Devastated by his wife's departure and later death, Keeler died in 1949 in Door County, Wisconsin, at the age of 45, after suffering a stroke brought on by stress, alcohol, and cigarettes. His contributions to the development of the polygraph are featured in the documentary film The Lie Detector which first aired on American Experience on January 3, 2023. Filmography References External links Finding Aid to the Leonarde Keeler Papers, 1899-1972, The Bancroft Library Biography of Leonarde Keeler American police detectives 1903 births 1949 deaths 20th-century American inventors