By Andrea Hargraves 
In the early 1920s, one community experienced an unprecedented growth in wealth. The Osage, a Native American tribe, suddenly became the most prosperous nation in the world in terms of per capita GDP. The impetus for the radical change was the discovery of vast quantities of oil in their lands, marking the beginning of an era of opulence and tragedy.
In the early 1800s, the U.S. government forced the Osage off their lands in Kansas and forcibly relocated them to a smaller area in southeastern Kansas. Under intense pressure from invading white settlers, the Osage family in 1870 agreed to sell their lands in Kansas and purchased a large tract from the Cherokee tribe in what was then Indian Territory, located in what is now northeastern Oklahoma, elEconomista says.
About 3,000 Osage crossed the Kansas-Oklahoma border on foot to their new homeland in 1871. The new Osage territory was made up of worthless, unarable land. Thus, in 1872, the United States Congress established a new reservation for the Osage Nation on land they owned, marking the final and permanent homeland of the Osage people, now in Osage County, Oklahoma.
What the Osage did not know was that treasure was hidden beneath this ground. It has been known since the seventeenth century that there were oil and gas leaks in some valleys in the eastern part of the reserve. But it was not until 1896 that the first oil and gas lease on Osage lands was granted.
Before the discovery of oil, the Osage were a people dedicated to agriculture, trade, and hunting. However, the arrival of the oil industry radically changed its fate. The sudden wealth attracted a wave of settlers and opportunists, including greedy businessmen, corrupt lawyers and even murderers, all eager to take advantage of the Osage's vast oil reserves.
Oil wealth changed life for the Osage, but it also caused one of the darkest events in U.S. history, known as the “Reign of Terror.” This period saw a series of brutal murders, manipulation, and machinations as unscrupulous individuals sought to exploit the Osage's newfound wealth.
The dark story of the Osage remained a mystery until relatively recently, when journalist David Grann shed light on the story in his work “The Moon Killers.” Now, thanks to the film of the same name directed by Martin Scorsese, the horrors the tribe faced during their reign of wealth and terror have been revealed.
The “Reign of Terror” was marked by brutal killings, manipulations, and arranged marriages designed to control the exploitation rights of the Osage. It is estimated that at least 60 members of the tribe were brutally murdered during this period, while others disappeared or fell ill under suspicious circumstances.
In the face of this horror, the Osage desperately sought justice. Their appeals reached the federal government, implicating the newly formed Bureau of Investigation, the predecessor to the FBI.
Although some cases have been solved and the perpetrators convicted, many crimes remain unsolved to this day.