Star and executive producer Leonardo DiCaprio said he and fellow producers decided to centre the film around the "twisted" but true love story of Ernest Burkhart, a white man, and Mollie, the Osage woman he married, to help drive home the human toll.
"When we made the shift to making Ernest and Mollie the centrepieces of the story ... it seemed like a dynamic shift," DiCaprio, who plays Ernest, told Reuters.
"We flipped the whole story on its head.
"We got to not only explore this very twisted relationship - we got to explore the Osage and the Osage community and how they were affected by all of this."
Killers of the Flower Moon debuted in US cinemas in October and is streaming on Apple TV+.
In the film, DiCaprio's Ernest gets caught up in the machinations of his Uncle William (Robert De Niro).Â
As part of his uncle's plans, Ernest begins poisoning his wife, Mollie (Lily Gladstone), while also acting as her nurse and protector.
Producers listened to input from Osage members, including descendants from that era, and often changed narratives based on their opinions, DiCaprio said.
"The Osage community, really they talked in great detail about that relationship, and even though it was an incredibly bizarre, twisted love story, there was love between them," he said.
