Danish private detective agency in Fredensborg and Copenhagen

The first woman in Denmark to run her own private detective agency in Copenhagen was Madame Martha Nielsen. She owned the "Copenhagen Female Private Detective Bureau" (Københavns kvindelige private Detektiv-Bureau). The agency was founded on October 29, 1903, and was located at 3 Bagerstræde Street in Copenhagen from 1908 to 1918. In 1918, Madame Martha Nielsen moved the agency to 20 Skjalm Hvidesgade Street in Copenhagen, where it remained for over 20 years. (Source: Dansk Kriminyt No. 21, December 1993.)

The bureau had the telephone number 1458, close to the police number at the time, 1448. This number remained the same throughout its existence. Through old advertisements published in the newspaper "Politiken," we discovered that the agency still existed in 1940, but we could not determine the date of its closure.

In 1930, Martha Nielsen published the book "A Life as a Female Private Detective" ("Et liv som kvindelig privatdetektiv"). This book is still available in the reading room of the Royal Library today. In 2024, it was reprinted and republished. Link: https://www.gucca.dk/et-liv-som-kvindelig-privatdetektiv-bog-p690343.

Here is what the agency's logo looked like in 1910:

Allan Pinkerton (1819–1884) founded the first private detective agency in the United States, the "Pinkerton National Detective Agency," in the 1850s, even before the country had its own intelligence service.

This agency, which often collaborated with local police, initially protected railroads from train robberies. It later became the precursor to the "Secret Service," the American intelligence service.

During the Civil War (1861–1865), Allan Pinkerton gained particular fame. He developed various investigative techniques still used today, such as "shadowing" (tailing suspects) and "undercover work." He notably saved President Abraham Lincoln from an assassination attempt by informing him of a plot to kill him.

In 2003, the "Pinkerton National Detective Agency" was acquired by Securitas and still exists today under the name "Pinkerton."

At the end of June 1884, Allan Pinkerton slipped on a sidewalk in Chicago. When he fell, he bit his tongue, which led to an infection. Not having consulted a doctor, this injury caused his death a few weeks later. Until his last days, he was working on creating a central database of criminals. This database still exists today and is now managed by the FBI.

Below is the logo of the "Pinkerton National Detective Agency":

Former French soldier (and former criminal) Eugène François Vidocq founded the world's first private detective agency in 1833, "Le Bureau des Renseignements Universels pour le commerce et l’industrie," located at 12 rue Cloche-Percé, 75004 Paris, France.

The agency's missions were to protect merchants from organized criminals and dishonest individuals who bought goods on credit, never paid their debts, and then resold the merchandise in markets at half price.

His personal experience as a criminal in Arras and Paris allowed him to understand the methods of offenders. Vidocq hired former convicts as detectives. The state attempted several times to close his agency, and in 1842, he was arrested for having a person imprisoned based on false accusations in a case of embezzlement he had solved. Vidocq claimed it was a plot to have him convicted. Sentenced to 5 years in prison and a fine of 3,000 francs, he was ultimately acquitted on appeal.

Eugène François Vidocq is credited with inventing:

• document management,
• criminology,
• ballistics (the science of studying the motion of projectiles),
• and creating the first plaster cast of a footprint.

The French police still use his teachings on anthropometry (measurement of the human body's dimensions) today.

He is also known for devoting time and money to charitable works and for never reporting those who stole out of necessity to survive.

He participated in the creation of the "sûreté police" (security police), which still exists today. Vidocq invented the private investigation industry, inspiring others to create detective agencies that helped businesses in social conflicts and offered armed guards as private militias for the economic sector.

Facts about Eugène François Vidocq:

• Born: July 24, 1775 (Arras, France)
• Died: May 11, 1857 (Paris, France)
• Burial place: Unknown
• Cause of death: Cholera (an infectious intestinal disease that can cause, within a few days, extreme diarrhea with fluid loss of up to 24 liters per day. It is caused by the bacterium Vibrio cholerae).