Good-government advocates pressed the House ethics committee Thursday to investigate three lawmakers with close ties to the defunct lobbying firm PMA Group.

In a letter, the groups called for the House Committee on Standards of Official Conduct to open an inquiry into Reps. John Murtha (D-Pa.), Peter Visclosky (D-Ind.) and Jim Moran (D-Va.), as well as “any other Representative who the Committee determines has been similarly involved with PMA.—

The letter’s authors, Democracy 21, Common Cause, Public Citizen and U.S. PIRG, want the committee to examine whether millions of dollars in campaign contributions that the firm generated for Members influenced the tens of millions of dollars in earmarks that lawmakers secured for PMA clients.

“We do believe, however, that the published reports … have raised serious ethics questions about House members and that these questions require an investigation of the PMA Groups matter by the Ethics Committee and a determination by the Committee as to whether House ethics rules have been violated,— the letter states. “We further believe that such an investigation is in the best interest of the House as an institution, the Representatives publicly involved in this matter and the American people.—

Under House rules, only Members are allowed to file formal complaints with the ethics committee. In their letter, the groups note that the committee is nonetheless allowed to initiate investigations without a formal compliant.