With the recent raids on a Virginia lobbying firm and Pennsylvania contractors with close ties to Rep. John Murtha (D-Pa.), federal agents appear to be circling the powerful defense spending chief.

But if Murtha, as Republicans hope, is in the cross hairs for improper campaign donations, other House Democrats may soon find themselves in the feds’ sights, too.

The PMA Group, the defense-appropriations-focused lobbying shop that the FBI raided in November, in recent years has spread millions of dollars in campaign contributions to lawmakers, mostly House Democrats. And the firm has magnified that largess by helping to wrangle untold sums for those Members from its dozens of clients.

The firm’s money trail could prompt new ethics headaches for House Democrats already dealing with the problems facing Murtha and Ways and Means Chairman Charlie Rangel (N.Y.). Rangel is facing an ongoing ethics committee investigation into his personal finances and fundraising for a New York education center that bears his name.

Murtha has not been accused of any wrongdoing, and there is no indication that he is a target of a federal investigation. The Pennsylvania lawmaker’s spokesman Matthew Mazonkey said the Congressman “has not been contacted by any federal agency, and no one is suggesting that Jack Murtha has anything to do with this. Period.”

But Republicans hoping to seize the ethical high ground from Democrats are already salivating at the prospect that a key ally of Speaker Nancy Pelosi (D-Calif.) may be in trouble.

“The signs that Rep. Murtha may be hiding serious ethical problems are clearer every day, but Speaker Pelosi continues turn a blind eye to the news about her hand-picked choice for House Majority Leader,” Michael Steel, spokesman for House Minority Leader John Boehner (R-Ohio), said in a statement. “Despite their campaign promises, the Democratic Leadership is still more interested in sweeping ethics problems under a rug than ‘draining the swamp.’”

A senior House Democratic aide shot back: “Taking ethics advice from John Boehner with Jerry Lewis (R-Calif.) and Don Young (R-Alaska) under federal investigation is like asking his advice about how to quit smoking.”

And while House Republicans made sure the news of the PMA raid was circulating Tuesday, House Democratic leadership was mostly mum. House Majority Leader Steny Hoyer (D-Md.), in response to a question about the raid, said Tuesday that the House ethics committee should “take under consideration any allegation that certainly is public and for that matter, any allegation that is privately made that bears substance.”

Murtha may be a top recipient of PMA funds, but employees of the Arlington, Va.-based shop have proved to be generous benefactors to a long list of lawmakers.

According to Federal Election Commission records, people identifying themselves as PMA employees have made just more than $2.7 million in campaign contributions since the beginning of 2001 — though about half of those donations have gone to the PMA corporate political action committee, which has in turn then doled money out to Members and other committees. The contributions mostly went to Democrats, though a handful of Republicans have benefited as well.

The total does not include thousands of dollars of contributions from family members who have not listed PMA as their employer. For instance, the FEC database includes about $70,000 in donations from a Jennifer Magliocchetti in Fairfax, Va. Some of these donations list her as a PMA employee, but others list her as a New York Yankees ticket sales agent and still others as a homemaker.

Even missing the full scope of PMA-related donations, it is easy to see a pattern in the firm’s contributions. The money tends to land in large chunks, particularly favoring Democrats on the House Appropriations Committee. And those lawmakers have frequently favored PMA clients with millions of dollars in earmarks.

In the spring of 2007, a new PAC created by the brother of Rep. Silvestre Reyes (D-Texas) raised $50,000 almost entirely from PMA Group staff and clients, and within weeks, those same donors reaped millions of dollars in earmarks from Reyes and other Members closely affiliated with PMA.

Later that year, Roll Call reported that Reps. Murtha, Jim Moran (D-Va.) and Peter Visclosky (D-Ind.) — all defense appropriators — had steered $100.5 million to PMA clients through 36 defense earmarks, while the firm and its clients contributed $542,350 to the trio in the first six months of the year.

Roll Call also reported on a small-business incubator supported by Visclosky that had more than a dozen tenants — but only the five companies that were clients of PMA received earmarks from Visclosky in the 2007 House appropriations bills. Together, those earmarks were worth $12.9 million.

By that time, the firm’s ties to the Indiana Democrat were firmly established: When Visclosky launched his leadership PAC in April 2003, the first 23 checks — worth $44,250 — that it received over the course of six weeks, all came courtesy of the firm and its clients. And after hiring Visclosky’s former chief of staff, Richard Kaelin, in 2004, fundraising support for the Congressman from PMA and its clients roughly doubled.

Rep. Norm Dicks (D-Wash.), the third-ranking member on the appropriations panel, has received $59,500 in donations from PMA employees since 2002, according to FEC records, including $9,000 on May 25, 2006. Dicks’ office did not respond to a request for comment.

PMA donations do not only follow the most senior committee members.

Rep. Tim Ryan (D-Ohio), a relatively junior appropriator, has pulled in $37,250 since June 2005 from PMA employees. Ryan spokesman Brad Bauman said the firm represents innovators and employers in the Congressman’s district.

“Congressman Ryan continues to look for opportunities to help these companies and others that improve our economy,” Bauman said in a statement. He added that Ryan is so far unaware of any allegations against the firm, beyond reports that it is under federal scrutiny. “Should that change, he will certainly consider any appropriate actions.”

Second term Rep. Christopher Carney (D-Pa.) has received $38,500 from PMA employees since February 2007, including $11,000 on Feb. 8, 2008. PMA’s donations make the firm the single largest donor for Carney’s re-election campaign in 2008, according to the Center for Responsive Politics. Employees of PMA client Gentex Corp. kicked in another $11,500, which places that firm in the top five of Carney’s re-election supporters.

Carney’s office did not respond to calls requesting comment.

PMA Group employees have donated $25,250 to Rep. Patrick Murphy (D-Pa.) since September 2006, which makes the firm one of Murphy’s top donors. That number does not include spouses of PMA employees, who have contributed several thousand additional dollars, and PMA clients, who have given thousands more.

Murphy spokesman Adam Abrams said the reports about the raid of PMA “are obviously very troubling, and we’ll be paying close attention as the details come out.”

Other Members who have received large amounts of campaign cash from PMA employees include: Murtha, $106,600 since 2002; Moran, $93,750 since 2002; retired Rep. David Hobson (R-Ohio), $54,145 from August 2002 to June 2007; Rep. Mike Doyle (D-Pa.), $27,000 since October 2004; and Reyes, $23,320 since February 2007.

Rep. Bill Pascrell (D-N.J.) has received $26,900 from PMA employees since June 2005, and the firm provided more than half the funding for Pascrell’s Silk PAC. Pascrell created the PAC in March 2007, and by October 2008, the group had raised about $90,000 in individual donations, $48,000 of which came from PMA employees. In October, Silk PAC received and influx of $36,500 from non-PMA donors.

Pascrell’s office did not respond to calls requesting comment.

PMA employees have scattered some contributions among Republicans, although in much smaller numbers. In addition to Hobson, FEC records indicate PMA employees have given $48,000 to former Sen. John Sununu’s Daniel Webster PAC since 2003 and $14,000 to the campaign of Zach Wamp (R-Tenn.).

The company’s PAC giving is much more bipartisan, spreading its contributions to dozens of Members in both parties.

Jennifer Bendery contributed to this report.