WASHINGTON -- The PMA Group, a Washington lobbying giant founded by a former staffer of Johnstown Rep. John Murtha, is closing amid federal scrutiny, according to sources speaking with WJACTV.com.

PMA, which has donated thousands of dollars to Murtha's campaign in recent years, has been a major benefactor of the Congressman's. PMA clients have received tens of millions of dollars in federal government earmark money. The Crystal City, Va.-based lobbying operation is expected to cease operation March 31.

According to multiple reports, federal investigators raided the PMA headquarters in November, triggering intense scrutiny of the lobbying group's campaign donations and government contacts. In the weeks since, PMA has disintegrated, with multiple employees seeking out new employment opportunities, according to multiple congressional sources. PMA spokesman Patrick Dorton declined to comment when reached by WJACTV.com.

PMA's close, controversial relationship with Murtha is raising questions about whether the veteran congressman is also part of the investigation.

Melanie Sloan, Executive Director of Citizens for Ethics and Responsibility in Washington told WJACTV.com, "Given Congressman Murtha's longstanding, close relationship with PMA, the fact that the firm is shutting down, largely because of a criminal inquiry, suggests Mr. Murtha ought to be huddling with his lawyers to prepare for criminal action against him as well."

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A Justice Department spokesman declined to comment when asked whether Murtha was a subject of an FBI investigation.

In January, federal agents raided the Pennsylvania properties of Kuchera Industries. Kuchera, like PMA, is a large campaign contributor to Murtha.

Murtha, whose spokesman did not return multiple e-mail and phone inquiries, is a prolific source of funding for Pennsylvania. He is among the leading source of federal earmark money. SEE FOR YOURSELF: LINK - Total Earmarks in 2008 Congressional Appropriations Bills