What to Know About ‘Killers of the Flower Moon’: A Guide to the Osage Murders

In the 1920s, at least 60 Osage people were murdered or went missing in Oklahoma. Their white killers often married the victims before dispatching them. With shares of the tribe’s immense oil profits at stake, the scheme made them rich.

Until one of them shot Anna Brown in the back of the head in May 1921 and dumped her body in a ravine, a killing so brutal that a recently formed organization of undercover officers, the precursor to the F.B.I., took notice. The agency conducted a sprawling investigation that culminated in the arrests of three of Brown’s relatives, including her brother-in-law, Ernest Burkhart, bringing an end to what the Osage called the Reign of Terror.

These events are the subject of Martin Scorsese’s new three-and-a-half-hour epic, “Killers of the Flower Moon,” which arrives in theaters on Friday. Based on David Grann’s nonfiction book of the same name, it stars Leonardo DiCaprio as Burkhart; Lily Gladstone as Mollie Kyle, the wealthy Osage woman he marries; and Robert De Niro as Burkhart’s scheming uncle, William King Hale, who is responsible for the whole operation.

Unlike Grann’s book, which also chronicles the birth of the F.B.I., Scorsese’s film focuses on the effects of the murders in the Osage community. Here is what you need to know about the real people and events dramatized in the film.

Who are the Osage?

The Osage once lived across much of the central United States. In the early 1870s, the U.S. government forced them to leave their land in Kansas and move to a rocky, presumably worthless reservation in northeastern Oklahoma.