The horrifying true story behind Leonardo DiCaprio’s new film

• DiCaprio’s new film Killers of the Flower Moon explores a terrifying true story
• Set in the 1920s, it focuses on the FBI’s investigation into a series of murders
• Two dozen Native Americans were killed during the Oklahoma killings

Leonardo DiCaprio’s new film Killers of the Flower Moon explores the sad true story of the “reign of terror” that left two dozen Native Americans dead.

The blockbuster, which is due for release in May, is based on the 2017 non-fiction book of the same name written by David Grann.

Set in the 1920s centers on the FBI’s investigation into a series of murders following the massacre of several members of the Osage tribe in Oklahoma.

But as film fans prepare for the crime drama to hit their screens, FEMAIL looks back at the horrific true story.

Killers of the Flower Moon focuses on a little-publicized chapter of American history involving the Osage Nation.

In the 1920s, the Osage tribe became wealthy almost overnight after oil was discovered beneath their land, earning more than $30 million in annual revenue at the height of the boom, according to Oklahoma Historical Society.

Underground minerals within the Osage Nation Reservation were tribally owned and held in trust by the government.

Mineral leases earned royalties paid to the tribe as a whole—with each grantee receiving an equal share, also known as headright.

But these rights could only be legally acquired by outsiders if they married into the tribe.

It was during this time that rancher William K. Hale, originally from Greenville, Texas, encouraged his vassal nephew Ernest Burkhart to marry Osage member Mollie Kyle (later Mollie Burkhart).

Burkhart, played by Leonardo DiCaprio, and his wife Mollie, played by Lily Gladstone, lived in Fairfax with Mollie’s mother, Lizzie Q.

Lizzie was the mother of four children, and in May 1921, the decomposed body of one of the other daughters, Anna Brown, was discovered in a remote ravine in northern Oklahoma.

He was found with a bullet hole in the back of the head but, as Brown had no known enemies, the case remained unsolved.

Just two months later Lizzie herself died under suspicious circumstances of suspected poisoning, although no proof was ever found.

Then another family member, Lizzie’s nephew Henry Roan, met a similar fate in January 1923 as Hale, played by Robert De Niro, fraudulently named himself as the beneficiary of the 25,000 life insurance policy dollars.

But the deaths in the family did not end there.

In March 1923, another of Lizzie’s daughters, Rita Smith, along with Rita’s husband, William Smith, and their housekeeper, Nettie Brookshire, were all killed when their home was destroyed by an explosion.

And, upon their deaths, Burkhart and Mollie inherited a fortune from the estates of her mother and brothers.

But the killings extended beyond the one family with an estimated 24 Osage Indians dying violent or suspicious deaths in the early 1920s, with newspapers at the time describing it as a “reign of terror.”

By this time, the authorities were becoming suspicious, and a concerned Osage tribal council sought the help of the US government.

Hale’s name came up early in the investigation as the mastermind behind the murders.

The so-called “King of the Osage Hills” was accused of bribing and intimidating others to do much of his dirty work as he sought to gain money and power.

The murders subsided when Hale, along with accomplices, including his nephew, were arrested in 1926.

Hale was formally convicted of his involvement three years later. He was paroled in 1947 after serving two decades of his sentence.

At the time, investigators also discovered that the killers had already begun poisoning Mollie in what would be the final piece of the crook’s masterplan.

Fortunatelyshe recovered and divorced her murderous husband after the trial.

The actors involved in the production have acknowledged the seriousness of the film’s true story.

Lily Gladstone previously shared a photo of Mollie Burkhart on Instagram along with a caption that read: “I consider it a true gift and great responsibility to be trusted with Mollie Burkhart and I will treasure her with both hands, close to my heart.

“My deepest thanks to the Osage Nation, it is a remarkable gift to welcome me and to be able to tell this story.”

Janae Collins also, who plays Rita Smith, wrote, “I am so grateful to the Osage Nation for allowing us to tell their story. This is one of the most painful and heartbreaking times in the history of the Wazhazhe people as well as Native American history and

“I take it very, very seriously as an actress and as a Lakota/Dakota and Apsáalooke woman. I am very grateful to Marty Scorsese for the honesty, diligence and care he has shown in this project. He and Leonardo have really put a bat for us (as natives) over the years, getting to the point where we’re ready to film.

“I’m so thankful/grateful for the love and support we have.”