In the 1920s, as many as 60 Osage, made wealthy by oil, were murdered one at a time in a complicated conspiracy to steal their money. Many were killed by their white husbands or relatives, who married them deliberately to kill them. Eventually, once white allies were killed, the FBI investigated; it was one of their first murder cases.
A new book is out on the subject, Killers of the Flower Moon, by David Grann. His interview on NPR’s Fresh Air outlines the story.