In 1850, Allan Pinkerton met a Chicago attorney by the name of Edward Rucker. Together, they formed the North-Western Police Agency, later known as Pinkerton’s National Detective Agency. Around 1855, Pinkerton noted an increased demand for private detectives. Businessmen, large and small, realized that many of their business losses involved employee theft, and so in ever-increasing numbers, they turned to agencies such as Pinkerton’s as a means of reducing their losses, and these clients became the foundation of the Pinkerton Agency’s business success.
The demand for more detectives prompted Pinkerton to run an advertisement in the Chicago newspaper for men interested in private law enforcement. As it turned out, Pinkerton’s was a phenomenally successful agency, particularly in the period leading up to, during, and after the Civil War [Note 1].In 1856, Mrs. Kate Warne visited the Pinkerton offices in Chicago and announced that she was interested in employment. Widowed at age 23, Mrs. Warne needed the work and decided that she was qualified for employment — not as a secretary, but as a female detective.
Her interest was highly unusual, but she was brilliant, in control, and eloquent. Pinkerton later described her as “a slender, brown-haired woman, graceful in her movements, and self-possessed.” Pinkerton was surprised that she was interested in detective work and told her that it was not his custom to hire women. Warne argued that women could be “most useful” in discovering secrets that would be impossible for a male agent to uncover. She argued that a woman could befriend the wives and sweethearts of criminals, and besides that, men like to brag about their accomplishments in front of women. Mrs. Warne also noted that women are better observers than men.
Pinkerton, impressed by her argument, hired Kate Warne. She became America’s first female detective. In 1858, Warne participated in an embezzlement investigation at Adams Express Company. Warne managed to learn through the primary suspect’s wife that he, one Mr. Maroney, an express agent, misappropriated company funds to the tune of $50,000.00. Warne’s investigation enabled the return of $39,000. A jury convicted Maroney and sentenced him to 10 years in prison.
Allan Pinkerton was so impressed with Warne that in 1860 he placed her in charge of the female bureau of Pinkerton’s and resolved to hire more women — another first in United States history.
In 1861, Allan Pinkerton was hired by the Philadelphia, Wilmington, and Baltimore (PWB) Railroad to investigate suspected secessionist activities and threats of damage to the railroad in Maryland. Pinkerton placed agents at various points in Maryland to investigate whether there was a basis for these concerns. As the investigation proceeded, Pinkerton became aware that the activity in Maryland wasn’t merely a threat against the railroad — it also involved a plot to assassinate Abraham Lincoln, recently elected to the Presidency. Kate Warner was one of the agents Pinkerton sent to Baltimore to investigate secessionist activities. It was Kate Warne who uncovered the plot against Lincoln in February 1861. Working undercover posing as a southern woman visiting Baltimore (complete with a thick Southern accent), she infiltrated several secessionist groups. In this capacity, Warne discovered many of the details about the assassination plot, including the place of the intended assault.
Lincoln publicized his inaugural train trip … one that would take him from his home in Springfield, Illinois through 70 cities, ending up in Washington, D. C. in time for his inauguration. At that time, the rail system configuration required that all southbound trains discharge and transfer their passengers in Baltimore, Maryland. The Northbound station ended on Calvert Street, and the southbound train route began at Camden Street. The distance between these two stations was about a mile.
This was the area where the assassins planned to strike. As Mr. Lincoln passed through the depot at Calvert Street to enter his carriage, a row would break out to divert policemen from the depot and leave Lincoln unprotected. At this point, secessionists would surround Lincoln and shoot him down. They then planned to escape to Virginia aboard a river steamer.
Pinkerton met with U. S. Representative Norman B. Judd and Mr. Lincoln on 21 February 1861 and revealed to them the information uncovered by his agents. For his part, Lincoln dismissed the plot’s existence, but if it did exist, he did not believe it deserved any serious concern. Only when a second source, Frederick W. Seward (the son of Secretary of State-designate William H. Seward), confirmed the plot did Lincoln finally agree that such a plot was feasible. Still, he steadfastly refused to cancel his planned itinerary. He did, however, agree to take measures to avoid entrapment.
At Harrisburg, Mr. Lincoln gave three speeches and participated in a flag-raising ceremony at Independence Hall. Afterward, he attended a high profile dinner party in his honor. During dinner, Lincoln’s secretary (John Nicolay) interrupted the party to excuse Lincoln on the pretense of an important matter. Lincoln changed into a traveling suit and carried a shawl to change his appearance. At the station, Kate Warne accompanied Lincoln, Pinkerton, and Ward Lamon [Note 2] aboard the train.
Lincoln’s train proceeded to Philadelphia, where he re-boarded a special train of the PWB to Washington. During the night of 22-23 February, Kate Warne remained awake during the night, disguising Lincoln and keeping guard. From this particular event, Allan Pinkerton devised his business slogan, “We Never Sleep.” Warne was a key factor in moving Abraham Lincoln safely to Washington, under the pretense that Warne was traveling with her “sick brother.” Lincoln’s train arrived in Baltimore at around 03:30 on 23 February, when Lincoln’s sleeping car was transferred to a Washington bound track.
Between 1861-65, Kate Warne served Pinkerton and the Union as a spy. Her ability to penetrate Southern social gatherings and befriending women who had relationships with Confederate men of power enabled her to provide Pinkerton (and Lincoln) with worthwhile military, political, and economic intelligence. When working undercover with Pinkerton, Warne would often pose as his wife — a ploy used to satisfy polite society’s curiosity.
According to historians, Kate Warne was instrumental in uncovering a sophisticated Confederate spy ring inside the nation’s capital involving Rose O’Neal Greenhow [Note 3]. Greenhow was a well-known socialite who developed close relationships with highly placed civilian and military officials, including former president James Buchanan, during the period before the Civil War. Greenhow obtained important information and then passed it along to her Confederate contacts.
In early 1861, Greenhow helped develop a pro-Southern spy network under Confederate sympathizer, U. S. Army Captain Thomas Jordan [Note 4]. When Jordan left the U. S. Army to accept a Confederate commission, he turned his spy network over to Rose Greenhow, who continued to funnel information to Jordan. Jordan helped to establish the Confederate Secret Service.
Greenhow managed to develop and nurture several important contacts, including pro-Southern members of congress, senior U. S. Army officials, through which she obtained the battle plans of General Irvin McDowell and passed them to Jordan, who then passed them to Confederate General P. G. T. Beauregard [Note 5].
At this time, Kate Warne was posing as a Southern sympathizer and established a relationship with Rose Greenhow. Greenhow was never hesitant to express her support for the Confederacy, nor was she unwilling to use her female charms to obtain information. Kate’s task was to obtain proof of Greenhow’s treason.
By early August, Greenhow had a feeling that her activities were being monitored and fearing that her network was in jeopardy, along with her concern for the safety of her daughter Leila, sent Leila to live with an older sister in Ohio. Her youngest daughter, called Little Rose, remained at home with her mother.
In mid-August, Pinkerton believed he had enough evidence against Greenhow to apply for a warrant for her arrest. With warrant in hand, Pinkerton agents raided Greenhow’s home and began gathering boxes of evidence. They quite literally dismantled Greenhow’s home and uncovered coded letters, Union battle plans, information about increasing the Union army’s size, diaries of Army units detailing their training programs, and maps of Washington’s defenses.
In addition to a vast range of military information, Pinkerton agents discovered love letters from the abolitionist Republican Senator Henry Wilson from Massachusetts, who gave her information on the number of heavy guns and artillery positions in Washington. Wilson served on the Congressional Military Affairs Committee [Note 6]. Pinkerton also discovered incriminating material from Union flag officers, indicating their willingness to provide Greenhow with information in exchange for intimacy with Greenhow.
According to one of Pinkerton’s agents, “There was not a distinguished name in America that was not found there (Greenhow’s home).” Pinkerton concluded that the United States may not have had a more dangerous enemy than Greenhow. In her memoirs, Rose referred to a female agent named Ellen, who searched her person for documents — discovering several. Some historians conclude that Ellen was actually Kate Warne. Warne became Greenhow’s primary guard and interrogator, and there is some evidence suggesting that Greenhow feared Warne (Ellen) and begged authorities not to leave her alone with Warne/Ellen.
Greenhow’s home actually became a holding facility for men and women arrested in connection with his investigation; Little Rose was allowed to stay with her mother in the Greenhow home. Even while under arrest, though, Rose Greenhow continued to pass Jordan messages [Note 7]. Greenhow was transferred to the Old Federal Prison on 18 January 1862 [Note 8].
Warne continued working for Pinkerton as Superintendent of Female Detectives after the Civil War and was instrumental in solving several “high profile” cases. Among these were the murder of George Gordon, a bank teller, and the theft of $130,000.00 in cash and attempted murder. In both cases, Warne disguised herself to ferret out the truth. In the first instance, she uncovered Gordon’s murderer and returned the money to the bank, and in the second, she foiled the plot to murder by poison two potential victims. So successful was Kate Warne that Pinkerton acknowledged her as one of his five best detectives.
Kate Warne passed away from “congestion of the lungs” on 28 January 1868 and was buried in Chicago, Illinois. She was 34 or 35 years of age.
- Abbott, K. Liar, Temptress, Soldier, Spy: Four Women Undercover in the Civil War. New York: Harper Collins, 2014.
- Blackman, A. Wild Rose: Rose O’Neale Greenhow, Civil War Spy. New York: Random House, 2005.
- Enss, C. Lady Pinkertons. True West Magazine, 2018.
- Fishel, E. C. The Secret War for the Union: The Untold Story of Military Intelligence in the Civil War. Boston: Houghton, 1996.
- McKay, E. A. Henry Wilson: Practical Radical, a Portrait of a Politician. Port Washington: Kennikat Press, 1971.
- Morn, F. The Eye that Never Sleeps: A History of the Pinkerton National Detective Agency. Bloomington: Indiana University Press, 1982.
- Pinkerton, A. The Spy of the Rebellion. G. W. Carleton & Co., 1883.
- Seiple, S. Lincoln’s Spy Master: Allan Pinkerton, America’s First Private Eye. New York: Scholastic Press, 2015.
- Walsh, R. The Untold Story of Kate Warne, America’s First Female Private Eye. Open Road Media, 2018.
 As the United States expanded its territories in the west, demand for fast and reliable transportation drove the construction of American railroads. These, in turn, became targets for train robbers. After solving a series of train robberies, Pinkerton came into contact with George McClellan, who was then serving as Chief Engineer and Vice President of the Illinois Central Railroad. His lawyer was a man named Abraham Lincoln. When the Civil War began, Allan Pinkerton served for two years as the Union Intelligence Service head. He headed off a plot uncovered in Baltimore, Maryland, for the assassination of President Lincoln. So thoroughly had Pinkerton infiltrated the Confederacy, he almost knew what their plans were before the ink had dried. In 1871, the U. S. Congress funded the creation of the Department of Justice. The congressional appropriation of $50,000.00 was insufficient to establish an investigation unit, so the DOJ contracted with the Pinkerton Agency to investigate alleged federal crimes.
 Ward Hill Lamon (pronounced “lemon”) was Lincoln’s self-appointed bodyguard. An associate of Lincoln since 1852, Mr. Lamon was a physically imposing man whose friendship with Lincoln led to frequent disagreements with Pinkerton over the matter of Lincoln’s safety. For instance, Lamon wanted Lincoln to carry a pistol and a knife on his person as he entered the nation’s capital; Pinkerton would not hear of it. He argued that it was unacceptable to have a new president assume his duties while armed in fear of his own safety. In this case, Lincoln agreed with Pinkerton.
 Maria Rosetta O’Neal (1813-1864) was born and raised on a Montgomery County, Maryland plantation. She was the third of five daughters of John O’Neale and Eliza Henrietta Hamilton. John was a planter and slaveholder who was murdered by his black valet in 1817. John’s murder forced his widow and children into poverty. Rose, as she was called from early childhood and her sister, Ellen, went to live with an aunt in Washington, D. C. In the 1830s, Rose met Robert Greenhow, Jr., a prominent doctor and a lawyer. Their courtship was well received in polite society, and they were married in 1825. Dr. Greenhow died in an accident in 1854. (Further note: Ellen married Dolly Madison’s nephew, James Madison Cutts, and in 1856, Ellen’s daughter Adele married Stephen A. Douglas, the senator from Illinois). After Dr. Greenhow’s death, Rose, influenced by Senator John C. Calhoun, became more sympathetic to the Confederate cause.
 Thomas Jordan (1819-1895) was a native Virginian who attended the USMA, class of 1840. Initially assigned to the infantry, Jordan served with distinction in the Mexican-American War. Upon promotion to captain in 1847, he was transferred to the Quartermaster Corps and served in various Southern garrisons through 1860. He resigned his Union commission on 22 May 1861 to receive a Confederate commission as a captain, but in June 1861, he was advanced to Lieutenant Colonel. After the First Battle of Manassas, Jordan was promoted to Colonel, serving as General Beauregard’s chief of staff. He was advanced to Brigadier General on 14 April 1862. After the war, he worked as an editor/publisher. Between 1868-1870, Jordan served as General-in-Chief of the Cuban Liberation Army. He returned to the United States, settled in New York City, and became a frequent writer of articles about the Civil War.
 Confederate President Jefferson Davis credited Greenhow with helping to ensure a Southern victory at the First Battle of Bull Run in July 1861.
 Senator Wilson was never charged with treason or espionage. Some historians contend that Wilson never passed damaging information to Greenhow, but rather his secretary might have been the culprit — but it is doubtful that his secretary wrote romantic letters to Greenhow. In any case, Wilson later served as Vice President of the United States under President U. S. Grant.
 Rose Greenhow never went to trial for her treason, proving a double legal standard in the United States at least since 1862. Union authorities released her (with Little Rose) on the condition that she stay within the Confederacy. She was escorted to Fort Monroe, turned over to Confederate authorities, and lived in Richmond, Virginia. She was subsequently used by President Davis as a female courier to Britain and France. She met with Queen Victoria of the United Kingdom and Napoleon III of France. In 1864, Greenhow became engaged to Granville Leveson-Gower, 2nd Earl Granville. Greenhow’s memoir was written in London, a best-seller throughout England. While attempting to return to North Carolina aboard a British vessel, the ship ran around near the Cape Fear River. Fearing capture and imprisonment, Greenhow transferred to a rowboat and headed for shore. A wave capsized the rowboat, and Rose, carrying on her person $2,000.00 in gold coin, was drowned. Her body was recovered, and she received military honors at her funeral in Wilmington, North Carolina.
 The Old Federal Prison briefly served as the nation’s capitol (1815-1817) and is now the U. S. Supreme Court building site.