WASHINGTON (Reuters) - A group that files ethics complaints against elected officials is requesting a U.S. Justice Department investigation into whether Republican presidential contender Newt Gingrich worked as an unregistered lobbyist.
Citizens for Responsibility and Ethics in Washington, which last year helped prompt the resignation of a U.S. senator, said on Thursday that it sent a complaint against Gingrich to prosecutors and the FBI.
It was unclear what the Justice Department would do with the complaint. Gingrich's spokesman and his lawyer did not respond to separate requests for comment on the complaint.
U.S. prosecutors have never brought a case under a 1995 law that requires someone to register with Congress as a lobbyist if he or she meets certain criteria, such as spending 20 percent of their time on lobbying activities.
A spokesman for the U.S. Attorney's Office in Washington, which would handle any potential case involving the lobbying law, had no comment. Failure to register as a lobbyist can be a civil violation or a crime.
Gingrich, who finished fourth in the Iowa Republican caucuses on Tuesday, has said he never worked as a lobbyist during the 13 years since he stepped down as speaker of the U.S. House of Representatives.
The question of whether Gingrich was a lobbyist arose during a debate in November. Asked about a fee he received from Freddie Mac, he said he served only as an adviser to the housing finance giant.
Since then the media have documented ties between Gingrich's consulting business and corporations with interests before Congress, such as healthcare companies. Critics say his work shows he profited off the influence and fame he gained in public office.
The request by Citizens for Responsibility and Ethics in Washington is the first publicly known complaint against Gingrich in the lobbying matter. Last month the same group requested an investigation by the Federal Election Commission into alleged corporation contributions to Gingrich's campaign.
The new complaint focuses on a 2003 debate over the expansion of Medicare, the federal health program for the elderly.
Gingrich tried to influence the debate while he was head of a coalition of healthcare companies that stood to benefit financially from potential changes, the complaint says.
"During 2003, Mr. Gingrich repeatedly met with and spoke to members of Congress and the Bush administration, both individually and in groups, regarding passage of the Medicare bill," it says.
Founded in 2003, Citizens for Responsibility and Ethics in Washington regularly makes accusations against lawmakers and candidates for alleged ethical or legal transgressions.
Its executive director, Melanie Sloan, is a former federal prosecutor who previously was a Democratic aide on the House Judiciary Committee.
The group filed the initial ethics complaint against Republican John Ensign, a U.S. senator who resigned in May 2011 amid accusations that he violated lobbying restrictions and obstructed justice.
On the Democratic side, the group in October persuaded the FBI to release documents related to a federal investigation of the late Representative John Murtha.
Reporting by David Ingram; Editing by Kevin Drawbaugh and Xavier Briand