Private investigators, eyes, and detectives  may seem like a profession that’s been around forever, but this is not the case.  Perhaps because their famous fictional counterparts have been around nearly as long, but in reality private detectives have been in use for around 150 years.
First documented in France in the first half of the 19th century, the first known private detective was a former criminal and inspiration for writers like Victor Hugo.  Eugene Francois VIdocq spent decades stealing, robbing, and escaping jails before turning his life around and using his skill set for good.  After years of working with the police he eventually founded Le Bureau des Renseignements, which is considered the first private detective agency and was primarily staffed by ex-convicts.
Because he introduced modern practices such as updated record keeping, ballistic reports, and going undercover, he is considered the father of modern criminology.
The first well known agency was founded by Allan Pinkerton in 1850. Â So influential was Pinkerton’s National Detective Agency in fact, their logo was how the term “private eye” came about. Â
The “eyes” have it. (Public Domain)
The Pinkerton agency is said to be responsible for the mug shot, and contributions to law enforcement.  At this time the agency was often used to mediate strikes and provide security, with Pinkerton himself saying they singlehandedly foiled an assassination attempt against Abraham Lincoln.  By the end of the century PNDA became one of largest firms of its sort in the world, and is still around today as a subsidiary to Swedish security company Securitas AB.
At this formative time for private detectives, they often filled the role of law enforcement, acting as police when their clients felt the police were too ill-equipped to handle a need or situation. Agencies were rarely hired by average citizens at this time, perhaps to due the pre-modernization of America thus the lack of excess funds for such hires.
Agencies were also hired to find the most infamous criminals of the time, such as Jesse James, Butch Cassidy, and the Sundance Kidd. Not until the roaring 20’s was it possible for everyday people to seek the assistance of a PI, which was in part due to the expansion of the middle class.
The uses for private detectives often changes with the eras as peoples needs are altered and technology evolves. Â In the past 20 years, strides have been made to require more licensing and certification to become a PI, perhaps in an effort to authenticate the industry from it’s looser, less reputable past (or at least that what the movies make it out to be). Â Even the term “private detective” is less en vogue then the current “private investigator” or LPI’s for similar reasons.
What’s for certain, PI work is an industry that responds to the problems of today, and shall continue to do so, always around the help control the chaos.