Rep. Maxine Waters, D-Calif., walks past a media stakeout on Capitol Hill in Washington. (AP Photo/Cliff Owen) (Cliff Owen/AP)

A report offering new details regarding the House ethics committee’s handling of the investigation of Rep. Maxine Waters (D-Calif.) has led to calls for a new probe — this time, of the panel itself.

Politico reported Monday that two of the committee’s former attorneys may have compromised the Waters investigation by improperly communicating with Republican committee members.

This followed a Washington Post report last December that the investigation had been derailed by infighting within the committee, and that the Democratic committee chairman’s attempt to fire two investigators had been stymied by the top Republican on the panel.

On Monday, the watchdog group Citizens for Responsibility and Ethics in Washington urged House Speaker John A. Boehner (R-Ohio) and Minority Leader Nancy Pelosi (D-Calif.) to appoint an outside counsel to investigate the committee.

“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 the House leaders. “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 new details in the Politico report cast serious doubt on the 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.

Waters faces allegations of improperly working to secure federal aid for a minority-owned bank in which her husband was a large investor.

The ethics committee had scheduled her trial for last November, but before it could begin, it was abruptly postponed as the panel announced it had come across newly discovered evidence in the case.

The panel’s chairman at the time, Rep. Zoe Lofgren (D-Calif.), suspended the two lead lawyers in the 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, accused Lofgren earlier this year of trying to oust Sovereign and Kim “without cause.”

Politico reported that Chisam had written to Lofgren late last year with concerns that the two attorneys had improperly shared information on another ethics case, involving Rep. Charles Rangel (D-N.Y.) 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.

Meanwhile, 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.

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.”

“Given that both current Members and staff are implicated” in these violations, Brand wrote, the case against Waters should be dismissed.

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

More on

The Fix: Why Republicans don’t fear default

2Chambers: Nearly 30 percent of House skips votes as debt-limit deadline looms

On cybersecurity, Congress can’t agree on turf

Poll: Little confidence in leaders to deal with debt issue