By Tom Morrow

In the late 19th century, the name of Allan Pinkerton became the most feared among the bad guys and the most respected by law-abiding citizens. His detective agency grew to more than 30,000 agents becoming the largest private army in America.
Pinkerton’s agency served as the forerunner of the U.S. Secret Service, as well as being retained by corporate America, most notably the railroads. The tycoons wanted Pinkerton to stop train robberies by gangs like those of Jesse and Frank James, the Younger brothers and the Hole in the Wall gang led by Butch Cassidy.
Pinkerton was a Scotsman who was born in Glasgow, Scotland on Aug. 25, 1819. He left school at the age of 10, read voraciously and was largely self-educated. Pinkerton was a cooper (barrel-maker) by trade who emigrated to the United States in 1842.
As early as 1844, Pinkerton worked for the Chicago abolitionist leaders, and his Illinois home was a stop on the so-called “Underground Railroad,” which sheltered runaway slaves from the South.
In 1849, Pinkerton was appointed the first police detective in Chicago. In 1850, he partnered with Chicago attorney Edward Rucker in forming the Northwestern Police Agency, which later became Pinkerton & Co, and finally Pinkerton National Detective Agency. The agency is still in existence today as Pinkerton Consulting and Investigations. Pinkerton’s business insignia was a wide-open eye with the caption “We never sleep.” The term “Private Eye” comes from that insignia. As the U.S. expanded in territory, rail transport increased. Pinkerton’s agency solved a series of train robberies during the 1850s, first bringing Pinkerton into contact with (the future Union general) George McClellan, then chief engineer and vice president of the Illinois Central Railroad, and Abraham Lincoln, who was that company’s attorney.
Prior to the Civil War, Pinkerton developed several investigative techniques still in use today. Among them are “shadowing” (surveillance of a suspect) and “assuming a role” (undercover work). When the Civil War began, Pinkerton served as head of the Union Intelligence Service during the first two years, foiling an assassination plot in Baltimore, Maryland while guarding Abraham Lincoln on his way to Washington, D.C.. His agents often worked undercover as Confederate soldiers and sympathizers to gather military intelligence. Pinkerton served on several undercover missions for the Union Army. Pinkerton’s Intelligence Service was the forerunner of the U.S. Secret Service.
Following Pinkerton’s service with the Union Army, he continued his pursuit of train robbers. He was hired by the railroad express companies to track down the outlaw Jesse James, but after Pinkerton failed to capture him, the railroad withdrew their financial support and Pinkerton continued to track James at his own expense.
After James allegedly captured and killed one of Pinkerton’s undercover agents (who was working undercover at the farm neighboring the James family’s farm), he abandoned the chase. Some consider this failure Pinkerton’s biggest defeat. He also opposed labor unions. The agency’s reputation was somewhat tarnished for the protection of replacement workers (so-called “scabs”) and the business property of the major industrialists, including Andrew Carnegie.
Pinkerton was so famous that for decades after his death, his surname was a slang term for a “private eye.” Hardboiled crime fiction novelist Dashiell Hammett was employed by the Pinkerton agency before becoming an author, and his experiences influenced the character of Nick Charles in “The Thin Man” series.
Allan Pinkerton died in Chicago on July 1, 1884. Reportedly, Pinkerton slipped on the pavement and bit his tongue, resulting in gangrene. Contemporary reports give conflicting causes, such as that he succumbed to a stroke or to malaria. At the time of his death, he was working on a system to centralize all criminal identification records, a database now maintained by the Federal Bureau of Investigation.