Killers of the Flower Moon is a 2017 nonfiction book by American journalist David Grann that tells the story of the so-called 1920s Reign of Terror, a period during which numerous Osage Nation members were killed in Oklahoma for their oil wealth—murders that for the most part went unsolved. The book details these killings and investigates who was responsible.

The Osage Nation, like many Indigenous tribes of North America, had been pushed west by white colonists, until finally settling in a rocky area of land in what would become the state of Oklahoma. They hoped that the poor soil, unfit for farming, would keep white newcomers from dislodging them yet again. However, when oil was discovered on Osage territory, the tribe became quite wealthy because it owned the headrights to the oil—these claims could not be bought or sold, only inherited. As a result, nefarious outsiders devised ways to steal the tribe’s money; when swindles failed, they resorted to murder.

Content Warning: The book describes incidents of extreme violence and hate-fueled violence; it also depicts racist anti-Indigenous stereotypes.

Plot Summary

The book is organized into three sections.

The first section introduces the Reign of Terror, whose victims were shot, poisoned, and involved in car accidents. Investigations by the authorities and private agencies mostly led nowhere; what’s more, several of those who investigated the deaths or sought help from the federal government also turned up dead. The killer, or killers, meanwhile, went free.

Mollie Burkhart’s mother and three sisters were all killed; the death of Mollie’s sister, Anna, offers a vivid example of the kinds of mysterious circumstances that accompanied most of the Osage murders. Mollie and Anna were married to the white Burkhart brothers, whose uncle, William Hale, was among the most prominent and influential citizens in the community. Hale pledged to use his resources and connections to help find Anna’s killer.

The second section focuses on the investigation of the murders by the Bureau of Investigation (the precursor of the FBI). Heading the investigation was Tom White, an old-style lawman from Texas. Together with his team of agents, he uncovered shocking evidence that Hale and the two Burkhart brothers were behind many of the murders. Hale, Ernest Burkhart (Mollie’s husband), and an accomplice were tried and convicted in court. The case helped to bolster the reputation of the Bureau after a series of scandals in the early 1920s; Grann ends this section of the book with a digression into the simultaneous rise of the Bureau and its head, J. Edgar Hoover, in the mid-20th century. Grann also outlines Tom White’s later career as prison warden, as well as his retirement years.

The final section describes Grann’s research trips to Oklahoma and Texas, in which he seeks answers to lingering questions in the case. He talks to several descendants of victims, including Mollie Burkhart’s granddaughter, Margie Burkhart. Grann learns that the Osage Reign of Terror actually lasted much longer than the official record shows: Many deaths were not classified as murders and many victims were targeted but not killed. The Bureau’s investigation focused on Hale as the mastermind behind the killings, but evidence from the 1910s and 1930s indicates that murders continued after Hale was incarcerated. Grann concludes that the killings involved and encompassed virtually the entire community of Osage County.