A subsidiary of Oklahoma-based BOK Financial Corp. has agreed to pay more than $1.6 million to settle charges that it concealed information from investors in municipal bond offerings to purchase and renovate senior living facilities, the U.S. Securities and Exchange Commission announced Friday.

The agency also filed a complaint in federal court against a former senior vice president at the bank, Marrien Neilson, saying she was mainly responsible for the failures of the bank’s corporate trust department while overseeing what turned out to be fraudulent bond offerings managed by Atlanta-based businessman Christopher F. Brogdon. Brogdon was charged with fraud this past November and was ordered to repay $85 million to investors.

Brogdon amassed nearly $190 million through dozens of municipal bond and private placement offerings in which investors purportedly earned interest from revenues generated by the assisted living community, nursing home or other retirement housing projects supported by their investment, according to the SEC. The businessman, however, secretly commingled investor funds instead of using the money to finance the project described to investors in the disclosure documents for each offering, the commission alleged. From the commingled accounts, he diverted investor money to other business ventures and personal expenses, according to the commission.

According to the SEC order announced Friday, the BOK Financial Corp. subsidiary, BOKF NA, failed in its gatekeeper role as indenture trustee and dissemination agent for Brogdon’s bond offerings. BOKF and Neilson, the commission said, became aware that Brogdon was withdrawing money from reserve funds for the bond offerings and was failing to replenish them, and that he had not filed annual financial statements for the offerings. BOKF and Neilson also knew that the nursing homes that were collateral for one of the bond offerings had been closed for many year, according to the SEC. Neilson, however, allegedly warned others that disclosing these and other problems could impair future business and fees from Brogdon, upset bondholders and cause regulatory issues for bond underwriters. Therefore, they decided not to inform bondholders as required, the SEC said.

“BOKF was in a crucial gatekeeper position to stand up for bondholders and notify them about material problems with the bonds but instead turned a blind eye and chose to protect Brogdon and the fees it collected from his deals,” said Lara Shalov Mehraban, associate regional director of the SEC’s New York regional office.

Since 2000, according to the order, BOKF has been the indenture trustee for 39 Brogdon bond offerings, through which the businessman raised more than $164 million. Seventeen of the offerings were issued between 2007 and 2015, for which BOKF received more than $1.4 million in fees in exchange for its related work. Fourteen of the offerings remain outstanding, with a remaining principal amount of more than $65 million.

Without admitting or denying the SEC’s findings, BOKF agreed to pay disgorgement of $984,200 of the fees the bank collected from its work with Brogdon. The bank also agreed to pay $83,520 in interest and a $600,000 penalty. BOKF terminated Neilson’s employment in July 2015 after an internal investigation and reported the misconduct to the SEC.

Brogdon was the CEO, president and director of Global Healthcare REIT at the time he was charged in November. He had been vice chairman and chief acquisitions officer of AdCare Health Systems from September 2009 to Oct. 13, 2015, according to the SEC.

In related news, securities attorneys in the Cleveland office of Peiffer Rosca Wolf say they have been retained by municipal bond investors to recover money they invested with Brogdon. The law firm filed a lawsuit on behalf of the investors, who are seeking to recoup their investments from third parties that allegedly assisted with the Brogdon bond programs.