In the late nineteenth century, the US Government drove the Osage Indians out of Kansas onto seemingly worthless land in Oklahoma. The discovery of oil beneath this land, the Osages made the Osage among the wealthiest people in the world.

Soon after the oil discovery, many in the tribe were murdered. Powerful white men decided that Native Americans were not entitled to the money and sought to seize it for themselves. This "reign of terror" continued for years, led by cattleman William King Hale, helped by his nephews Ernest and Byron Burkhart. Ernest married an Osage woman Mollie Kyle. All of Mollie's immediate family died soon after the wedding – by poison, gunshot, and a home explosion.

Even before the murders, the Native Americans were already the victims of systemic racism. To prevent Indians from controlling their own finances, the government frequently appointed white "guardians," who purchased items for them - often reselling them to the Indian at wildly inflated prices. Merchants frequently increased prices dramatically when selling to Indians.

Investigators of the murderers disappeared or were found dead. Eventually, the FBI (then known as the "Bureau of Investigation") resolved the case, charging and convicting William Hale and Ernest Burkhart.

David Grann's 2017 book "Killers of the Flower Moon" chronicles the murders and the ensuing investigation.

One can be forgiven for thinking this book is a murder mystery. Most of it reads like a suspense novel, highlighting character personalities and relating conversations.

In the final chapters, Grann pivots and describes his investigation decades after the murder, revealing that the death count was probably much higher than recorded in the official statistics.

This chapter of American history is largely forgotten. Grann's book and Martin Scorsese's film adaptation remind us all how far greedy men will go to exploit others. It is a lesson we should never forget.