Police History: How the first female sleuth thwarted a presidential assassination plot

Many aspects of Kate Warne's life are up for debate but we do know that she helped save the life of a president and helped build the reputation of a private detective agency


On August 23, 1856 a young widow entered the offices of Allan Pinkerton to apply for a position. Pinkerton assumed she was there for a clerical job, but Kate Warne had her sights on becoming a detective. Flabbergasted, Pinkerton wondered, “How could a woman possibly be a detective?”

Warne explained she would be the perfect undercover operative because no one would suspect a woman to be engaged in such a non-traditional activity. She said men’s tendency to brag to women would enable her to gather information from any man in an undercover capacity, and that women in the 19th century would rarely pass on their husband’s secrets to anyone except for another woman who had gained their confidence.

Pinkerton was sold. He hired Kate over the strong objections of his brother — his partner in the business. Kate would work the rest of her life for Pinkerton, and Allan would never regret his decision.

Adams Express Company
It is difficult to give a full accounting of Kate Warne’s career. Much of what she did was done in an undercover capacity. A fire in Pinkerton’s Chicago Office in 1871 destroyed most of her case files.

However, one case she is known to have cracked was the Adams Express Company $50,000 ($1,475,000 in today’s money) embezzlement case.

Kate went undercover and befriended a Mrs. Maroney, whose husband was the prime suspect. In this capacity Warne was able to not only gather enough information to secure a conviction and a ten-year sentence for Mr. Maroney, but she was also able to recover $39,515 of the stolen money.

Saving Lincoln
Kate’s most famous case was made in 1861. She was asked to verify rumors that there may be a plot to kill President Lincoln, who had just been elected. Kate — who was a master of disguise and accents — took on the persona of a Southern upper-class woman named Mrs. Barley. She then infiltrated the social circles of the pro-secessionist elites of Baltimore. She took on a Southern accent and wore the black and white cockade of secession.

She was not only able to verify that there was a serious plot, but she was able to discover, the who, what, when, where, and how of the assassination scheme.

Kate and Allan Pinkerton immediately arranged a meeting with President-elect Lincoln. They gave him the details and convinced him to allow them to make arrangements so that he could survive long enough to be inaugurated.

Kate and Allan — who became life-long investigation partners — teamed up and convinced the president to change his plans. Instead of arriving in Washington to crowds and fanfare, Lincoln slipped through Baltimore and safely into Washington quietly disguised as Kate’s invalid brother. He was cloaked, and walked stooped while supported by a cane on one side and Kate’s arm on the other. Lincoln’s family did not even know his travel plans had been altered.

The ruse was coordinated and carried out primarily by Kate. She was armed and was said to have never slept throughout the trip. Some historians believe that this may be the origin of Pinkerton’s motto “We Never Sleep.”

The Civil War
Kate Warne and Allan Pinkerton were utilized by the Union throughout the Civil War for gathering hard intelligence. Kate repeatedly infiltrated the South, posing as a Southern Belle. Kate was so good at acting and disguises she would at times even pose convincingly as a man if she felt this would serve her purpose better.

Kate was so effective Pinkerton employed many more women in this role. He insisted that they be trained by Kate.

After the war, Kate continued on with Pinkerton, working cases involving everything from corruption to marital infidelity. Pinkerton put her in command of all of his female detectives who owed their jobs to the success of Kate Warne.

Death and Legacy
On January 28, 1868 Kate Warne died of pneumonia at the age of 35. Allan Pinkerton, who many believe was in love with the slim, brown-haired detective, was at her bedside and holding her hand when she passed. Allan had her buried in the Pinkerton Family Plot next to Timothy Webster. Webster was a Pinkerton man who was captured by the South and executed as a spy for the Union.

When Alan Pinkerton died he arranged to be laid to rest next to Kate Warne.

Because of the fire and the secrecy of her work, many aspects of Kate Warne’s life are up for debate. Even the correct spelling of her name is not known for certain. Pinkerton records spell her name Warne and yet it is spelled Warn on her tombstone.

What is known about Kate was she helped save the life of a president and built the reputation of a private detective agency, whose procedures would inspire the FBI, CIA, Secret Service, and detective divisions of local and state agencies all over the nation.

She was a woman detective, in a day when most would say a woman could not do such a job. Yet she did that job in a manner that very few would ever do better. Kate Warne was an accomplished private investigator, superb spy, and savior of a president.

Pinkerton’s memoirs did not confirm nor deny his feeling of love for Kate, but did acknowledge he held her in the highest regard as a detective. In fact, Pinkerton said that he gave all the credit for the Pinkerton Detective Agency becoming an efficient, honorable organization to Timothy Webster and Kate Warne.

Pinkerton also said of Kate, “She never let me down.”

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