Washington (CNN) -- A group of 69 congressional Democrats called on the House Ethics Committee on Thursday to immediately release a special counsel's report dismissing claims that Rep. Maxine Waters' rights were violated during the panel's continuing inquiry into alleged misconduct on the part of the 11-term California congresswoman. Failure to release the report, the Democrats warned, would only expand the cloud of controversy hanging over the investigation.

On Wednesday, the Ethics Committee's bipartisan co-chairmen sent a letter to Waters that referenced special counsel Billy Martin's findings in explaining the panel's unanimous conclusion that her due-process rights had not, in fact, been violated.

They also stressed that the panel is entitled to extend its roughly three-year inquiry into allegations that Waters, D-California, improperly sought federal assistance in 2008 for OneUnited Bank, a minority-owned bank in which her husband held a financial interest. The bank ultimately received $12 million in bailout funds.

Waters insists that her efforts were part of a broader push to help minority-controlled financial institutions during the financial meltdown.

Among other things, Waters has complained about the Ethics Committee's supposed violations of her constitutional right to a speedy and public trial, and railed against the secrecy surrounding the panel's proceedings. Defenders of the top African-American legislator have raised questions about the role of race in the panel's investigation.

Waters has also questioned the propriety of earlier communications between GOP committee members and staff investigators. Last winter, six members of the panel, including five Republicans, recused themselves from the investigation.

In Thursday's written response to the Ethics Committee co-chairmen, the 69 House Democrats insisted that the panel "immediately release Mr. Martin's report, which forms the basis of their determination to dismiss Representative Waters' due process concerns."

The group argued that without "the public, the Congress, and Representative Waters being able to review the findings included in this report, the integrity of the Committee's process will be further called into question."

The members noted the panel's admission that one committee staff member had invoked the Fifth Amendment right against self-incrimination when questioned about the investigation. They also cited findings of "inappropriate and/or racially insensitive remarks" on the part of unnamed staff members.

"Considering that it was the conduct of the Committee that necessitated Mr. Martin's investigation in the first place, which came at the cost of up to $800,000 to the U.S. taxpayer, we feel it is absolutely essential that the Committee move forward with absolute transparency and release Mr. Martin's report," the Democrats said.

In Wednesday's letter to Waters, the panel's co-chairmen dismissed Waters' complaints about improper discussions between investigators and various committee members, noting that there is no ban on such communications. They also insisted there is no evidence that insensitive remarks, racial or otherwise, affected the panel's decision-making process.

The Ethics Committee hired Martin in July to review the case after multiple reports of possible improper communication among committee attorneys and lawmakers on the panel.

The initial investigation into 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 summer 2009.