WASHINGTON -- A top labor adviser to GOP presidential hopeful Mitt Romney stepped down from his volunteer role with the campaign not long before he was publicly implicated in a federal ethics investigation, according to a Romney campaign aide.

The inspector general of the National Labor Relations Board has asked federal investigators to examine whether Peter Schaumber, a former NLRB board member and erstwhile Romney adviser, may have been involved in violations of the Hatch Act, the federal law that prohibits civil servants from engaging in partisan politics.

The Hatch Act request stems from an earlier investigation by the labor board's inspector general that found that NLRB board member Terence Flynn had allegedly violated the agency's ethical code by sharing sensitive information with outsiders, including Schaumber, while serving as counsel last year. Flynn was notified Dec. 5 that he was being investigated. According to the aide, Schaumber left the campaign in December. The NLRB investigation first became public in March and now appears to be widening.

According to an April 3 letter, David Berry, the labor board's inspector general, forwarded his investigation to the U.S. Office of Special Counsel to see whether the correspondence between Flynn, a Republican, and Schaumber warranted "further investigation by the Hatch Act Unit."

Nancy Cleeland, an NLRB spokeswoman, said the inspector general does not comment on investigations.

Adam Miles, a spokesman for the Office of Special Counsel, confirmed that the agency had received the letter but would not comment further. "Our policy is not to confirm or deny whether we're investigating a Hatch Act complaint," he said.

Barry Coburn, a lawyer for Flynn, said in an emailed statement, "We are unaware of any basis whatsoever for any allegation that Mr. Flynn violated the Hatch Act. His contacts with Mr. Schaumber, his friend and former colleague, were not illegal in any respect."

On Thursday Rep. Elijah Cummings (D-Md.), the ranking Democrat on the oversight committee, sent a letter to committee chairman Rep. Darrell Issa (R-Calif.) asking for further investigation of Flynn's and Schaumber's actions. In the letter, Cummings chided Republicans for aggressively pursuing an investigation into lavish spending by the General Services Administration while being much slower to look for potential wrongdoing by a Republican NLRB board member and a Romney campaign adviser.

"In contrast [to the GSA case], you have been silent on the NLRB Inspector General's report, and you have taken no action whatsoever in response to my request," Cummings wrote. "You have called no hearings, conducted no interviews, and sent no document requests."

"[T]he Inspector General has now informed my staff that he has identified multiple additional improper disclosures of confidential inside information to Mr. Schaumber that he believes are even more serious than those he identified previously," Cummings also wrote.

The NLRB is the federal agency tasked with enforcing labor law and handling disputes between employers and unions. The board has drawn the fury of Republicans and industry trade groups over the past year as it has issued a string of decisions and rules considered friendly to labor groups. With the board taking considerable political heat from pro-business conservatives, Democrats like Cummings have been eager to highlight a possible board-related scandal involving Republicans.

Flynn was named to the committee in a recess appointment by President Barack Obama in January. According to the inspector general's investigation, Flynn allegedly passed along "the most confidential of agency information" to Schaumber and former board member Peter Kirsanow while Flynn was counsel to then board member Brian Hayes. The agency information allegedly included case lists, preliminary votes and internal deliberations.

This story has been updated to include the timing of Terence Flynn's notification about an investigation and of Peter Schaumber's departure. It has also been updated with the statement from Coburn.

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