WILLISTON, N.D. (AP) – The leader of an oil-rich American Indian nation is accused of using his position to benefit from business partners' lucrative oil field contracts and attempting to extort money from other companies for the go-ahead on projects at Fort Berthold Indian Reservation in North Dakota.

The allegations are laid out in a report by Kansas City, Missouri-based law firm Dentons based on investigation by the firm and led by former U.S. Attorney Stephen Hill. The report also describes a close business relationship between Mandan, Hidatsa and Arikara Nation chairman Tex Hall and a man indicted in a pair of murder-for-hire cases.

The findings were presented to the tribes' elected body, the Tribal Business Council, in August. But a 66-page-long section of the report wasn't released to the public until Monday, after tribal members protested.

A statement released by Hall's office called the report a “sham” and claimed it was commissioned by the chairman's political opponents. In a primary election Tuesday, just a day after the report was released to the public, Hall did not qualify for general elections set for November.

“At the end of the day, let's just call this what it is – a smear campaign whose sole purpose is try to grab power for themselves,” said Hall in the statement.

The Associated Press was not able to reach Hall by phone Wednesday.

Tribal attorney – and candidate for chairman – Damon Williams said he initiated an investigation into Hall's business dealings with felon James Henrikson earlier this year. However, the Tribal Business Council then hired Dentons to do an independent investigation.

According to the Dentons report, Hall's company, Maheshu Energy LLC and Henrickson's company, Blackstone LLC, entered an agreement in January 2012. Hall also leased his garage to Henrikson and his wife for $5,000 a month for the company to use.

Hall told investigators that Henrikson's wife began managing Maheshu in early 2012.

After the agreement with Maheshu, Blackstone was hired by a tribal employee to do work for the nation. In May 2012, the nation's council was presented with two invoices totaling nearly $180,000, and the council approved them, with a vote that included Hall.

Blackstone was told that invoices for an additional $390,000 would not be paid as that work was not approved by the council. On July 7, 2012, Hall intervened, signing a memo authorizing the payment to Blackstone and bypassing the council.

The report says Hall at no point told the council about his conflict of interest as required in the tribes' ethics code.

The investigation also found that Hall attempted to get between $1.25 million and $1.6 million from oil company Spotted Hawk Development LLC before it would be allowed to work on the reservation. Hall claimed that he was owed the money for a previous business deal with an executive.

Hall then contacted the Bureau of Indian Affairs and asked that it delay approval of the Spotted Hawk project and allow more time for comments. Hall later wrote to the bureau saying Spotted Hawk had not abided by its drilling commitments. In making contacts with the bureau, the report says Hall did not disclose his business interests in the matter.

Henrikson is in jail on federal weapons charges and was indicted on federal murder-for-hire charges in the killing of Doug Carlile and the disappearance of Kristopher “K.C.” Clarke, according to court documents released Wednesday.

Carlile was gunned down by a masked intruder in his Spokane, Washington, home in December. Clarke disappeared in early 2012. He was last seen at a facility used by Henrickson's company, Blackstone.

Tex Hall