Capuano has funds linked to lobbyist

But Capuano has failed to return or give away at least another $47,500 that employees of the firm, PMA Group, and its associates, had given to a separate political action committee that he created in 2005, MASS PAC, according to a Globe analysis.

Asked about the discrepancy, a spokeswoman for his US Senate campaign, Alison Mills, said the failure to scrub the PAC account was an oversight. She said his political staff is now going through records to identify PMA-related contributions to MASS PAC, an entity known as a leadership PAC, which many politicians operate to raise and donate funds to further their political careers and causes they support.

“We were focused on making sure that every dollar donated to the Capuano for Congress Committee from PMA-related entities was identified and donated to charity,’’ Mills said in a statement.

“We were not focused on the leadership PAC at the time because those funds did not directly benefit the congressman. We regret the oversight and will donate any PMA-related contributions from the leadership PAC to charity.’’

Capuano, however, had only about $34,000 in his MASS PAC account on Oct. 1.

Capuano announced in March, as the federal investigation heated up, that he was giving PMA-related donations to Boston-area charities. That amount, according to Mills, was $64,500 and covered donations going back to 1999, Capuano’s first year in the House.

Capuano, a Somerville Democrat, said he purged the funds from his campaign committee because he holds himself “to a higher standard.’’ Capuano had led the House leadership’s efforts in 2007 to strengthen ethics rules.

PMA Group, one of Washington’s most influential lobbying firms, disbanded earlier this year after its fund-raising activities came under the scrutiny of federal prosecutors. The firm, which the FBI raided in November, specialized in securing earmark funds for its clients, most of whom are defense contractors. The firm in 2006 successfully persuaded lawmakers to earmark $100 million for their clients, according to a study by the nonpartisan Citizens for Responsibility and Ethics in Washington.

Among lawmakers who had received PMA-related donations, Capuano, by his amount collected, was ranked 10th earlier this year by another nonpartisan group, the Center for Responsive Politics. That ranking, however, was based on $57,000 he collected from 2001 to 2008 that was connected to the lobbying firm. By adding the $47,500 Capuano raised for his PAC from those connected with the firm from 2006 to 2008, Capuano would rank fourth out of more than 125 lawmakers listed.

Capuano’s earmarks to the firm’s clients in or near his 8th Congressional District totaled $4.4 million in the past two years. He has defended those funds as “perfectly appropriate,’’ and said the process for awarding them was transparent.

PMA’s employees and its own political action committee have given to several members of the Massachusetts congressional delegation, though in smaller amounts. US Senator John F. Kerry got $6,000; the late Senator Edward M. Kennedy, $2,500. US Representative Stephen F. Lynch pulled in $19,000, and another member of the House, John F. Tierney, received $2,000.

The New York Times reported earlier this year that PMA is being investigated for allegedly using front donors to give, in excess of campaign contribution limits, on behalf of Paul Magliocchetti, who founded the lobbying firm in 1989 and is a focus of the probe. Magliocchetti has been a close associate of US Representative John P. Murtha, a powerful Pennsylvania Democrat who has also been a target of controversy.

Capuano, since launching his campaign to succeed Kennedy in the Senate, has not shied away from Murtha - a close colleague who chairs a powerful defense appropriation subcommittee - even as the controversy swirls in Washington. Capuano attended a Murtha fund-raiser in Boston in September, though other members of the Massachusetts delegation stayed away.