The House Ethics Committee on Wednesday announced it has appointed an outside counsel to pick up the long-delayed investigation of Rep. Maxine Waters (D-Calif.) and review whether committee members and staffers acted inappropriately in the months leading up to a trial that was postponed just days before it was set to begin last November.

“Serious allegations have been made about the Committee’s own conduct in this smatter by Representative Waters and others,” Ethics Chairman Jo Bonner (R-Ala.) and ranking member Linda Sánchez (D-Calif.) said in a joint statement. “The entire Committee has therefore directed that a thorough review of all of these serious allegations will be the very first task of the outside counsel’s engagement.”

Pressure had been building for the committee to act on the Waters matter since her trial was postponed last November and sent back to an investigative subcommittee for further review. Two staffers were placed on administrative leave following the cancellation and internal committee documents published by Politico this week showed that the committee’s former staff director thought the staffers’ improper behavior had likely compromised the investigation.

Waters and watchdog groups seized on the leaked documents as an example of the committee’s partisan dysfunction.

“The [committee’s] misconduct is of such a fundamentally improper level that it cannot be cured by reliance on any other device, including employment of an outside counsel,” Waters attorney Stan Brand wrote in a three-page letter to the committee Tuesday. “This Committee can never conduct an impartial and unbiased inquiry into this matter.”

A group of watchdog organizations that included the Campaign Legal Center, Common Cause, Citizens for Responsibility and Ethics in Washington, Democracy 21, the League of Women Voters, Public Citizen and U.S. PIRG on Wednesday called for the hiring of an independent counsel.

“We strongly urge the Ethics Committee to promptly engage an outside counsel to continue and complete the Waters investigation. The Committee should also establish a reasonable timetable for the resolution of this longstanding matter,” the letter to the chairman and ranking member said.

The committee has retained Billy Martin, a partner in the law firm Dorsey & Whitney, as outside counsel on the Waters case. His past clients include former Sen. Larry Craig (R-Idaho), who was arrested in a bathroom of the Minneapolis airport for allegedly soliciting sexual activity.