Of course Sherlock Holmes would be the most famous one, but unfortunately he’s a fictional character created by Sir Arthur Conan Doyle.
One of the first most famous Private Detectives 婚前調查 was Allan Pinkerton (1819 – 1884). He was by the side of Abraham Lincoln during the civil war. One of his more famous achievements was foiling an assassination plot against President Lincoln in Baltimore, Maryland. What many people don’t know is that he the father of several major investigative techniques such as surveillance of a suspect, known as ‘shadowing’ at the time, and also undercover work (he called it “assuming a role”).
Pinkerton served as the head of the Intelligence Service from 1861-1862 and used his men for undercover operations. They would pretend to be sympathizers of the Confederacy in order to gain vital military intelligence.
He also created the Pinkerton National Detective Agency. Some say that at one point it employed more men than the United States Army. The darker side of Pinkerton’s history included suppression of labor riots. Even to this day certain labor organizers use the word “Pinkerton” to describe those who side with the management.
Second most famous private detective is Eugène François Vidocq (1775-1857) – Was a French man with a very rough past who became one of the most famous detectives of all times. In his early life he had many run-ins with the law. He started as a teenager who stole silverware from his father. As an adult he went on to commit more serious crimes including fraud and being a raider while pretending to be an army soldier.
He turned his life around and started using his extensive experience as a former criminal to fight crime. He introduced plain clothes police officers who went undetected in seedy parts of French cities.
He also invented a tamper-proof paper used on checks. Once the compound was applied on a check it was no longer possible to discretely add additional numbers. He was also the first to employ ballistics examination to solve a case.
When a French noble woman was shot dead, he examined the size of the bullet. He was able to determine that the original suspect’s gun was not used in the shooting. He then examined the gun of her lover and the size matched. Presented with the evidence the suspect confessed to murder.