A raid by more than a dozen FBI agents on the Albany offices of the lobbying and consulting firm of the former head of the state Republican Party is part of an investigation that sources said may be connected to a Republican who served in Congress, John Sweeney, and concern a wider federal probe of influence peddling on Capitol Hill.

Double-parking their cars, about 15 agents descended on the State Street suite of the former party official, William Powers, and herded the employees into a room while the agents searched for files.

Sources said the raid was linked to Mr. Sweeney, who represented New York’s 20th district for four terms before a losing a re-election bid in 2006 to a Democrat, Rep. Kirsten Gillibrand.

Mr. Sweeney is a longtime friend of Mr. Powers, whose lobbying firm hired Mr. Sweeney’s then-wife, Gaia Ford, after they got married in 2004. Sources said the investigation possibly involves the relationship between federal earmarks to government contractors and the firm, Powers & Company.

Investigators are looking into whether Mr. Sweeney was collecting money outside of campaign contributions by steering business to the firm, sources said. The probe is said to extend beyond Mr. Sweeney and could be a broader investigation of corruption involving legislators in Washington.

Messrs. Sweeney and Powers did not return calls for comment. The Albany Times Union, which first reported the raid, quoted an attorney for Mr. Powers as saying that his client was not a “target” of the probe and was cooperating with the investigation.

Ms. Ford, who is divorced from Mr. Sweeney, left the firm soon after Mr. Sweeney left office.

Before serving in Congress, Mr. Sweeney was the executive director of the state Republican Party, serving under its former chairman, Mr. Powers, a former top aide to Senator D’Amato who ran the state party for than a decade,

FBI officials declined to comment on Friday’s action other than to confirm that the firm had been raided. “The FBI conducted investigative activity at that location last week relating to an ongoing investigation,” a spokesman for the FBI’s office in Albany, Paul Holstein said.

Mr. Sweeney was a members of the powerful House Appropriations Committee, which controls spending, including earmarks or pork-barrel expenditures.

In his four terms, he delivered to his district more than $280 million in federal funding.

He served on the homeland security committee and as vice chair of the Transportation, Treasury and Housing and Urban Development Subcommittee, a position from which he brought funding to expand Albany International Airport.

The Washington Post in 2006 reported that Mr. Sweeney and other members of the appropriations committee had political action committees run by current and former lobbyists with business before the committee.

His contest against Ms. Gillibrand was one of the most contentious in the 2006 election, which resulted in Democrats taking control of the House for the first-time in 12 years.

Days before the election, a police report of a 911 call that Mr. Sweeney’s wife had made in December 2005 in which she was said to have alleged that her husband was “knocking her around” was leaked to the press.

Ms. Ford in a later statement denied that Mr. Sweeney had physically harmed her and said she summoned the police to her home because an argument she had with her husband had spun out of control. “There were never any injuries to me. Neither John nor I are perfect. But we love each other deeply,” she said.

Mr. Powers, who has withdrawn from public view since stepping down as Republican state chairman, was once one of the top political power brokers in New York, credited with invigorating a debt-ridden party and steering it electoral victory around the state.

One of his main accomplishments was identifying an obscure state senator, George Pataki as gubernatorial material and guiding him toward an upset victory over Governor Cuomo in the 1994 election.

Mr. Powers was a state co-chairman of Mayor Giuliani’s presidential bid, leading his fund-raising effort in New York.