In 2006, the PMA Group, a powerhouse Washington, D.C., lobbying firm, added to its board of directors two Floridians who were not lobbyists and apparently had no connection to politics, but who became prodigious donors to the firm’s favored Members of Congress.

The firm is now a prime player in a federal investigation that appears to be focused on campaign contributions and could tarnish several high-ranking Members of Congress who have received donations from the company’s employees and clients.

John Pugliese, one of the board members the company added, has been described in campaign finance records as a sommelier at the Ritz-Carlton hotel on Amelia Island, a beach resort town in the northeastern corner of Florida. The other, Jon Walker, is currently the marketing director for the Golf Club of Amelia Island, a luxury golf course.

From June 2005 to the end of 2008, the two men donated more than $160,000 to Congressional campaigns that were receiving support from other PMA employees and clients.

Neither Walker nor Pugliese appears to have ever made a campaign donation before June 2005, and neither ever registered to lobby.

In almost every case, Federal Election Commission records list Walker and Pugliese donating the same amount to the same candidate (or candidates) on the same day. In most cases, other PMA employees also donated to those candidates on those days, but only Walker and Pugliese appear to be donating in tandem.

On Oct. 16, 2008, Walker and Pugliese made their last donations, $1,000 each to now-Sen. Mark Warner (D-Va.). The FBI raided PMA’s Arlington, Va., offices in November, and people familiar with the case suggest that federal agents are investigating the firm’s campaign donations.

PMA spokesman Patrick Dorton would not comment on the donations by Pugliese and Walker, saying only that the two “were members of the PMA Board of Directors.”

Walker did not respond to phone calls and e-mails requesting comment for this story. Pugliese could not be reached; calls to a phone number listed in his name were not answered, and a person answering the telephone at the Ritz-Carlton restaurant could offer no information about Pugliese other than “he does not work here anymore.”

PMA’s campaign contributions have attracted attention for several years. Roll Call has reported on several occasions that the firm and its clients have provided tens of thousands of dollars for influential Members of Congress who have secured earmarks for the client companies.

People listing PMA as their employer have donated about $2.7 million to political action committees and candidates since 2001, according to FEC records, but that number does not include tens of thousands of dollars worth of donations made by people affiliated with the firm who did not list PMA as their employer. Searching the FEC database for PMA employees turns up only about $35,000 worth of Pugliese’s and Walker’s donations.

Roll Call identified $82,500 worth of campaign contributions attributed to Pugliese and $86,500 attributed to Walker in the FEC database.

PMA’s founder, Paul Magliocchetti, is a former staff member for the House Appropriations Subcommittee on Defense, which Rep. John Murtha (D-Pa.) now chairs. Murtha is one of several Members who have doled out millions of dollars in earmarks to PMA clients.

The list of lawmakers benefiting from PMA largess reads like a who’s who of regulars in the “Pennsylvania corner,” named for the back-row aisle seat on the Democratic side of the House chamber that unofficially belongs to Murtha.

More often than not, Murtha is there during House votes, surrounded by fellow members of the Pennsylvania delegation, favored appropriators and others from similar working-class districts. It’s a physical power center in the House, where Murtha and his lieutenants trade information and favors and hash out deals.

At various times this week, Murtha could be spotted in his perch, as the familiar cast filled in seats around him or milled in the aisles nearby. They included Democratic Reps. Bill Pascrell (N.J.), Marcy Kaptur (Ohio), Carolyn McCarthy (N.Y.), Patrick Murphy (Pa.) and Jim Moran (Va.) — all, to varying degrees, PMA beneficiaries.

For example, PMA employees have donated at least $25,000 to the campaigns of Rep. Mike Capuano (D-Mass.) and have also ponied up $46,500 for Capuano’s political action committee — MASS PAC — since the end of 2006. During that time period, the PAC took in only $11,350 in donations that were unrelated to PMA. Capuano is a regular visitor to “Pennsylvania corner.”

Murtha’s spokesman has said there is no indication the FBI is investigating the Congressman, though the FBI earlier this year raided two Pennsylvania defense contractors that have also received earmarks from Murtha.

PMA employees and clients have not contributed only to Democrats. Former Sen. John Sununu’s (R-N.H.) Daniel Webster PAC took in about $340,000 from May 2003 to October 2008, according to FEC records. About $74,000 of that came from PMA employees, clients or family members.

The firm’s employees also donated heavily to former Rep. David Hobson (R-Ohio), and a few other GOP Members received donations from either employees or PMA’s own PAC, which shut down on Thursday after returning about $28,000 in contributions to its donors.

Jude O. Marfil contributed to this report.