After four hours of deliberation, a 12-person federal jury found the Cannon Ball district chairman guilty of sexually abusing a young girl.
Robert Fool Bear Sr., 54, was convicted Thursday on three counts of sexual abuse of a child and one count of incest. The jury acquitted him of physically assaulting the girl.
Though the counts refer to incidents recounted at trial, the allegation was that Fool Bear raped the girl repeatedly for at least four years, beginning when she was 10 years old.
U.S. District Judge Daniel Hovland scheduled sentencing for Aug. 23. Fool Bear faces a minimum of 30 years in prison.
The lead witness at trial was the young woman who testified to years of sexual abuse at the hands of Fool Bear. The lead question before the jury was whether the troubled girl could be trusted.
After the verdict was announced, Hovland commended the young woman, who was seated in the audience, for speaking out.
"It takes a lot of courage to come into a federal courtroom and testify in a case like this," Hovland said. "I hope someday you can weather this well, go on with your life and put all this chaos behind you."
He asked the U.S. Attorney's Office and FBI to investigate potential charges against anyone who knew of and did not report the abuse.
Fool Bear, who was in the community on electronic monitoring before trial, was taken away in handcuffs from the courtroom after a quick hug with his wife. He maintained his innocence before and during trial.
During the three-day trial, Assistant U.S. Attorney Gary Delorme called upon the young woman, medical experts and FBI agent to prove his case. They testified that the girl was sexually and physically abused by Fool Bear, which may have contributed to the complex post-traumatic stress disorder she suffers.
Fool Bear chose not to testify on his own behalf. His attorney Carey Goetz defended him by raising doubt for the jury about the young woman's credibility. She also questioned whether expert testimony truly corroborated the girl's story.
Delorme said after trial he hoped the conviction would encourage other young people on Standing Rock to report abuse.
Goetz said the question of whether to appeal would not be decided until after sentencing.
Fool Bear was district chairman of the 900-person town since 2005. Most recently, he was vocal about wanting the Dakota Access Pipeline protesters to move out of the area. He argued they were harming community resources, such as the gym, and preventing North Dakota from reopening Highway 1806 for months. He led meetings in January at which residents passed a resolution ordering protesters to leave.
According to Title 20 of Standing Rock tribal laws, Fool Bear's seat shall be forfeited due to the conviction, and Cannon Ball will need to hold a special election within 60 days.