Washington (CNN) -- The House Ethics Committee prepared Friday to dismiss charges of alleged wrongdoing against California Democratic Rep. Maxine Waters, ending a tumultuous investigation that lasted roughly three years and may have cost taxpayers up to $1.3 million.
Waters has been accused of improperly seeking government assistance for OneUnited Bank, a minority-owned bank in which her husband held a financial interest, during the 2008 financial meltdown. The bank received $12 million in bailout funds.
The 11-term Los Angeles-area congresswoman repeatedly insisted her efforts were part of a broader push to help minority-controlled financial institutions during the crisis.
A special counsel, attorney Billy Martin, has determined "there is not sufficient evidence in the record to prove violations" of House rules, said Rep. Bob Goodlatte, R-Virginia, head of a subcommittee examining the matter.
Goodlatte, stressing that panel members are prepared to follow Martin's recommendation, made his remarks during a rare public ethics hearing held hours before the House adjourned for the fall campaign season.
Martin did conclude, however, that Waters Chief of Staff Mikael Moore -- the congresswoman's grandson -- engaged in "specific actions" that "are in fact violations of the standards and rules of the House regarding conflicts of interest," Goodlatte noted.
Moore has insisted he was unaware of Waters' financial interest in OneUnited when he repeatedly sought to intervene on the bank's behalf.
The ethics panel, following Martin's guidance, may issue a letter of reproval to Moore.
Kentucky Rep. John Yarmuth, the top Democrat on the subcommittee, called the matter "complicated," and said Waters "faced a difficult balancing act between representing minority banks and avoiding a conflict due to her own financial interests."
Waters attended Friday's hearing, but did not address the panel or speak to members of the media. Moore told panel members he had a "heavy heart," and said the idea that he "disrespected the House is a very difficult pill to swallow."
Over the course of the ethics panel's lengthy investigation, Waters accused committee members of violating her constitutional right to a speedy and public trial, and railed against the secrecy surrounding the panel's proceedings.
Among other things, Waters questioned the propriety of communications between GOP committee members and staff investigators. Last winter, six members of the panel, including five Republicans, recused themselves from the investigation.
Defenders of the top African-American legislator also raised questions about the role of race in the panel's investigation.
In the summer of 2011, Martin was hired to take charge of the investigation -- at a cost of up to $800,000. Last month, House Ethics Committee members voted unanimously to spend as much as another $500,000, further retaining Martin as special counsel.
The initial investigation of Waters was led by the nonpartisan Office of Congressional Ethics, which was established in 2008 at the prompting of then-Speaker Nancy Pelosi, D-California. The office referred the matter to the House Ethics Committee in the summer of 2009.