Investigators with the FBI are expected to interview a former staffer of Rep. Michele Bachmann next week.
The FBI joins the Federal Election Commission, congressional investigators, an Iowa Senate panel and an Iowa police department in looking into various aspects of Bachmann's unsuccessful bid for the White House.
Former Bachmann aide Andy Parrish will speak to the FBI after Memorial Day, said Parrish's lawyer, John Gilmore.
"He'll cooperate fully," Gilmore said. "He's not been told the exact parameters of the interview. He has been told he's not the subject of the investigation."
Until he was fired by Bachmann in early 2012, Parrish had been one of her closest advisors, serving as campaign manager and chief of staff. Federal investigators appear most interested in potential campaign finance violations by the Bachmann campaign though Bachmann herself is not necessarily their target.
One of the allegations involves Guy Short, a political consultant who helped establish Bachmann's political action committee, MICHELEPAC, who went on to serve as the political director of her presidential campaign. A former Bachmann staffer, Peter Waldron, has alleged that Short may have broken campaign finance laws by receiving payments from MICHELEPAC that should have properly come directly from the campaign.
Waldron and Parrish have both also said that Kent Sorenson, an Iowa state senator who was the campaign's state chairman, received payments from MICHELEPAC designed to skirt Iowa Senate ethics rules. The Iowa Senate recently appointed an investigator to look into those allegations.
Through their lawyers, neither Short nor Bachmann said they had yet been contacted by the FBI.
"The FBI has not contacted Guy Short and he has done nothing wrong," said Short's lawyer, Christopher DeLacy. "The individuals who are pushing these allegations appear to be motivated by some sort of political vendetta."
"We have not been contacted by the FBI and have no reason to believe that they are conducting an investigation," said Bachmann's lawyer, William McGinley, in a statement. "As we have stated from the beginning, none of the allegations involve Representative Bachmann."