Kate Warne was the first female detective in the United States.
Described by Allan Pinkerton as a slender, brown haired woman, there is not much else known about Warne prior to when she walked into the Pinkerton Detective Agency in 1856. Born in New York, Warne became a widow shortly after she married. Warne was left as a young childless widow in search of work. In answer to an ad in a local newspaper, Warne walked into Pinkerton's Chicago office in search of a job. There is still debate whether or not she walked in with intentions to become a detective or just a secretary. Women were not detectives until well after the Civil War. Pinkerton himself claimed that Warne came into his agency and demanded to become a detective. According to Pinkerton's records, he
"was surprised to learn Kate was not looking for clerical work, but was actually answering an advertisement for detectives he had placed in a Chicago newspaper. At the time, such a concept was almost unheard of. Pinkerton said " It is not the custom to employ women detectives!" Kate argued her point of view eloquently - pointing out that women could be "most useful in worming out secrets in many places which would be impossible for a male detective." A Woman would be able to befriend the wives and girlfriends of suspected criminals and gain their confidence. Men become braggarts when they are around women who encourage them to boast. Kate also noted, Women have an eye for detail and are excellent observers."
Warne's arguments swayed Pinkerton, who at 10 o'clock on the morning of August 23, 1856, employed Warne as the first female detective. Pinkerton soon had a chance to put Warne to the test. In 1858, Warne was involved in the case of Adams Express Company embezzlements where she was successfully able to bring herself into the confidence of the wife of the prime suspect, Mr. Maroney. She thereby acquired the valuable evidence leading to the husband's conviction. Mr. Maroney was an expressman living in Montgomery, Alabama. The Maroneys stole $50,000 from the Adams Express Company. With Warne’s help, $39,515 was returned. Mr. Maroney was convicted and sentenced to ten years in Montgomery, Alabama.
This was just the beginning of Warne's career, she later went on to solve many more cases until she died shortly after the Civil War. She suddenly caught pneumonia on New Year's Day, 1868, and died on January 28 with Pinkerton at her bedside. She is buried in the Pinkerton Family Plot in Chicago Illinois' Graceland Cemetery. The grave is marked in the Graceland Cemetery under the name of "Kate Warn"; it states that she died of congestion of the lungs at the age of 38. She was buried January 30, 1868.