GREAT FALLS, Mont. (AP) – Montana’s Chippewa Cree Tribe must pay thrice-elected tribal chairman Ken St. Marks more than $648,000 for ousting him from office based on unsubstantiated allegations that he broke tribal laws, a federal agency ordered.

The U.S. Interior Department found in December that the tribe violated federal whistleblower laws by removing St. Marks from office in March 2013. St. Marks argued, and Interior agreed, he was targeted because he helped with a federal investigation that led to many convictions or guilty pleas for fraud and corruption on the Rocky Boy’s reservation.

The office of the inspector general released its report Friday saying it agreed with the Interior Department’s finding.

The “Chippewa Cree Tribe acted wrongfully toward St. Marks,” the report states, and “failed to substantiate ... with clear and convincing evidence” any of the seven charges leveled against St. Marks as justification for his removal from office in March 2013.

“Moreover, the numerous criminal indictments and convictions of Chippewa Cree Tribe employees and officials create significant concern for the department about the welfare of the Chippewa Cree Tribe’s government and its members,” the report said.

The inspector general’s office ordered the tribe to pay St. Marks for his entire elected term along with attorney and other costs.

“The tribe respectfully disagrees with the solicitor’s opinion and is evaluating its options regarding that opinion,” tribal attorney Rich Zack told The Associated Press on Wednesday. The tribe has 60 days to appeal the decision.

St. Marks was elected as tribal chairman two more times, and twice more he was ousted by the tribal business committee. The committee alleged St. Marks violated seven tribal laws including sexual harassment, unauthorized purchase of a vehicle using tribal funds, and unlawfully hiring and dismissing tribal employees.

St. Marks said the allegations were false and an attempt to punish him for cooperating with federal investigators.

Problems with the tribe’s governance continue, St. Marks said, and he argued the Interior Department needs to do more. He said nonelected people are serving as councilmen on the business committee and the federal government continues to give the tribe money.

“The place is being run by a bunch of thugs right now,” St. Marks told The Billings Gazette.

The inspector general’s order does not direct the tribe to reinstate St. Marks.