When William King Hale arrived in what is now Osage County, Oklahoma, around 1902, he was so poor he had to live in a tent. By the 1920s, he was so rich and powerful that people lived in terror of getting on his bad side. He had become known as the “King of the Osage Hills.”

He would go on to be convicted as the ruthless mastermind behind the Osage Murders, a shocking spate of killings that became the FBI's first major case.

A 1926 newspaper account described Hale as about 5’7” and 155 pounds, with “a splendid physique” and “unusually large” chest. His walk, it added, was “erect and springy.” A later author remarked on his “thick glasses, which gave him a [deceptively] benign, friendly look.”

Hale’s rise from cowboy to king coincided with the discovery of oil on the lands owned by the Osage Nation, making the Native American tribe the wealthiest people, per capita, on earth. Not being a member of the tribe, Hale had no claim on the Osage riches. But he knew how to get his piece of the action: He would steal it.

In what was either a fortunate coincidence or a cynical scheme, one of Hale’s nephews had married an Osage woman. Her annual income from the oil rights in 1917, the year of their marriage, was $2,608.99, about $82,000 today. Not only that, but she stood to inherit the estates and oil rights of her relatives, were they to die before her.

Hale figured that could be arranged.

Over half a decade, at least nine people would die in the murder spree Hale set into motion—some shot, some poisoned, three killed in an explosion that leveled their home. Most were members of the Osage nation, but others were white residents who either knew too much or simply got in the way. By some estimates, the death toll was even higher, anywhere from 24 to 60 or more. Many suspicious deaths simply went uninvestigated.

Too rich and too smart to bloody his own hands, Hale instead enlisted accomplices and made sure he had solid alibis. Even locals who suspected his involvement figured his wealth and political connections would keep him beyond the reach of the law. Then, due to the persistence of some surviving tribe members, J. Edgar Hoover and the FBI took an interest in the case, and Hale’s luck changed.

Hale was all but forgotten for decades, until the 2017 publication of David Grann’s Killers of the Flower Moon, which director Martin Scorsese adapted into a 2023 movie of the same name, with Robert DeNiro stepping into Hale’s villainous boots.

William King Hale was born near Greenville, Texas, on Christmas Eve in 1874 to what one longtime acquaintance called a “large, respectable and wealthy family.” His father was a farmer and rancher, and at age 16 young Bill decided to leave home to become a cowboy. For the next few years he bounced between Texas and the Oklahoma Territory, buying and selling cattle, some of which he was accused of rustling. “He is the most energetic man I ever knew,” the same acquaintance recalled in a 1926 newspaper interview. “He never loitered. Even when he crossed the street, he acted as if he were going after something big.”

Around 1902 and now married to a young schoolteacher, Hale settled in the Osage hills in Northern Oklahoma, where he and his wife spent their first spring living in tents. Because of some unspecified financial reverses, he was $10,000 in debt (about $350,000 in 2023 dollars). After working for other ranchers for several years, he formed a partnership with two local bankers and began leasing grazing land from the Osage. Eventually he’d hold the leases on some 45,000 acres and own another 5,000 acres outright. His other holdings would grow to include financial interests in a bank, a general store and perhaps most appropriately, a funeral home.

But for the ambitious Hale, that was clearly not enough. He knew that the real wealth wasn’t on the Osage grazing lands, but in what lay deep beneath them.

Oil had been discovered under Osage lands as early as 1890s, but it wasn’t until 1907 or so that business began to take off. Members of the Osage nation owned the oil rights collectively and divided the proceeds equally among themselves through what was known as “headrights.” By 1926, according to the Oklahoma Historical Society, the “average Osage family of a husband, wife, and three children” was receiving more than $65,000 a year (more than $1.1 million today).

Among those benefitting from the gusher of oil money was Mollie Burkhart, a tribal member and the wife of Hale’s nephew Ernest Burkhart. By some accounts, Hale himself had urged the young man to marry her.

Starting in 1918, a remarkable string of tragedies struck Mollie's family. First, her younger sister Minnie, age 27 and seemingly healthy, succumbed to a mysterious “wasting” disease. In May 1921, her sister Anna Brown was shot to death. Their mother, Lizzie Kyle, died in July, possibly of poisoning. Henry Roan, a cousin, died in another shooting in January 1923. Two months later, Lizzie’s other daughter, Rita Smith, was killed along with her husband and their housekeeper when an explosion tore through their home. All their wealth and oil rights transferred to Mollie and Ernest.

For good reasons, Mollie feared she might be next. That meant Ernest would get everything, putting it well within reach of his uncle, William King Hale, who had good cover. Long known as a prominent community member, Hale had constructed a benevolent facade as a generous friend to the Osage.

In the spring of 1923, tribal elders called on the federal government to do something. The Justice Department turned the case over to the newly formed Bureau of Investigation, as the FBI was then known. Its probe would run for the next three years.

Agents arrived to “an almost impenetrable wall of fear,” Don Whitehead wrote in The FBI Story (1956). “People who were afraid to talk and witnesses who might have given information had long since disappeared.” Prominent area police, doctors and others stayed silent because Hale had long since drawn them into collusion. Four undercover agents were eventually able to break the case, in part by getting Ernest Burkhart to talk.

In January 1926, Hale was indicted by a federal grand jury for the murder of Henry Roan. Roan had been killed on federal rather than tribal land, giving the government jurisdiction in the case. Hale’s motive, prosecutors maintained, was a $25,000 life insurance policy he had taken out on the man’s life. The alleged triggerman, John Ramsey, identified in newspapers as a “cowboy farmer,” was indicted on the same charge.

The first attempt at a trial was derailed due to a legal technicality. The second, which began in July, ended in a hung jury. The men were then retried in October and before the month was out, both were convicted of first-degree murder.

Hale’s lawyers successfully appealed the conviction, leading to a fourth trial, in January 1929. This time, Hale was convicted once and for all. His sentence: life in prison.

Through Hale’s multiple trials, courtroom observers constantly remarked on his steely calm. “Should Hale be given a death penalty,” one reporter wrote in August 1926, “some say he will help the executioner adjust the rope around his neck, and will go to his death with the smile that seldom leaves his face.”

When he left the courtroom that October after hearing the guilty verdict, Hale was “in a cheerful frame of mind,” the Associated Press noted, adding that Hale’s lawyers said he was still “jovial” the next morning.

Three years later, when Hale testified at his 1929 retrial, a reporter detected “a voice that held no tremor and a demeanor that bore no apparent anxiety.” When the court clerk read the guilty verdict, still another reporter observed, “the defendant gave no sign of emotion.”

William King Hale spent the better part of the next two decades in the federal penitentiary at Leavenworth, Kansas, or on its nearby prison farm, by all accounts a model prisoner. His release on parole in July 1947 came as a surprise to the Osage people, who believed he had been put away for good.

“In our minds there is no doubt that Hale was the ring leader in the mass murder of our tribesmen,” one prominent member of the Osage said. “His good conduct in prison does not mitigate the fact. I personally think he should have been hanged for his crimes.”

The FBI continued to keep tabs on Hale after his release. A 1956 memo in the FBI files, addressed to J. Edgar Hoover, reported that he was living in Montana and working at a “motor-restaurant-drive-in combination.” In recent years, he’d also held jobs on a ranch and as a dishwasher in the Range Riders’ Bar and Café, the agent noted.

Hale died in August 1962 in a Phoenix nursing home and was buried in Wichita, Kansas. The one-time King of the Osage Hills was 87.