(Charles Dharapak/AP)

The watchdog group Citizens for Responsibility and Ethics in Washington on Monday sent a letter to House Speaker John Boehner (R-Ohio) and Minority Leader Nancy Pelosi (D-Calif.) urging the leaders to appoint an outside counsel to investigate the ethics committee.

The request follows a Politico report Monday morning that revealed two of the committee’s former attorneys may have compromised the Waters investigation by improperly communicating with Republican lawmakers on the bipartisan ten-member panel.

“At this point, far more important than an inquiry into the conduct of any specific member of Congress is an investigation into the committee itself,” CREW executive director Melanie Sloan wrote in the letter. “A thorough review of the committee’s actions in the Waters case should be conducted by well-respected outside counsel. ... It is imperative for House leadership to step in and take decisive action to reinvigorate and instill public and member confidence in the ethics process.”

The letter from CREW is the latest twist in a long-running controversy surrounding the ethics committee and its handling of the investigations into Waters and Rep. Charlie Rangel (D-N.Y.). It is also comes as the new details revealed in the Politico report throw serious doubts on future of the Waters case as well as on the ability of the secretive panel to carry out its mission of overseeing members’ ethical conduct.

In a statement Monday evening, Waters’s attorney, Stan Brand, said that the Politico report and its accompanying documents “leave no doubt that the House Ethics Committee violated both its own rules and Representative Waters’ constitutional rights during its investigation of her matter last Congress.”

“(The committee’s) behavior also demonstrates that the Committee was driven to bring a flawed case and to ignore Committee rules imposed to insure fairness and due process,” Brand said. “Unfortunately, as would happen in prosecutorial misconduct of this nature in the judicial system, there is no federal judge to order dismissal. Nonetheless, based on the facts of the case and the record of Committee misconduct, the only remedy that vindicates the principals of the quasi-judicial functions of the Committee is immediate dismissal with prejudice. No other remedy exists to cure this misconduct.”

“Given that both current Members and staff are implicated in these documents, any other suggested remedy would lack legal credibility and would confirm an unprecedented level of bias against my client,” Brand continued. “Given this sample of damaging evidence of the Committees misconduct, we fully expect the Committee to act in good faith in this matter. If need be, we will explore all of our options to bring this matter to a conclusion.”

The committee had scheduled a trial for last November in the Waters case; the California Democrat faces allegations of improperly working to secure federal aid for a minority-owned bank in which her husband was a large investor. But the trial was abruptly postponed days ahead of its scheduled date as the panel announced it had come across newly-discovered evidence in the case.

The panel’s chairwoman at the time, Rep. Zoe Lofgren (D-Calif.), suspended the two lead lawyers in the Waters investigation, former federal prosecutors Morgan Kim and Stacy Sovereign, over a dispute with the committee’s top attorney, Blake Chisam. Chisam later left the committee and has since joined a top immigration law firm.

Rep. Jo Bonner (R-Ala.), the current chairman of the committee, earlier this year accused Lofgren of having dismissed Sovereign and Kim “without cause.”

But Monday’s Politico report shows that Chisam had written to Lofgren late last year with concerns that the two attorneys had improperly shared information on the Rangel case with several of the panel’s Republican members; Chisam also wrote to Lofgren that Kim and Sovereign had improperly withheld information from Waters’s defense team.

The report also reveals that Kim and Sovereign wrote to each other as well as to Republican members of the committee that Chisam had withheld evidence that could have been damaging to Rangel, including an allegation that the New York Democrat had improperly solicited millions of dollars from AIG.

CREW and several other watchdog groups in March called on the Ethics Committee to resume its investigation of Waters. But the panel had remained without a top lawyer until May, when it announced that it had hired Daniel A. Schwager, a former counsel to the Senate Select Committee on Ethics.

In its statement Monday, CREW echoed the statement by Waters’s camp that the case against the California Democrat had been compromised. The group stopped short, however, of calling for the entire investigation to be scrapped.

“Given the serious nature of the charges against committee and its staff, Rep. Waters is correct, there can be no case against her,” CREW said in its letter. “The committee should reconsider whether to pursue the case against Rep. Waters and, if it decides to go forward, disregard all previous work done by the committee on the case, starting afresh from the date of the referral by the Office of Congressional Ethics.”