Once thought to be a serious contender for the Republican presidential nomination, Rep. Michele Bachmann (Minn.) saw her campaign implode last year amid mass staff defections and accusations of gross mismanagement. Now, that disastrous campaign has put her in the crosshairs of federal investigators, who want to know whether her alleged mismanagement included any unethical or illegal behavior.

As The Daily Beast first reported Monday, the Office of Congressional Ethics has opened an investigation into Bachmann's failed campaign, asking former staffers about allegedly deliberate campaign finance violations, like under-the-table payments and illegal transfers of funds. The OCE is tasked with investigating ethical violations by members of Congress, and can pass cases along to the House Ethics Committee if it deems them worthy of further action.

Bachmann, through a lawyer, denied that she had done anything wrong.

"There are no allegations that the congresswoman engaged in any wrongdoing," her lawyer, William McGinley, said in a statement to the media. "We are constructively engaged with the OCE and are confident that at the end of their Review the OCE Board will conclude that Congresswoman Bachmann did not do anything inappropriate."

According to The Daily Beast, multiple former staffers confirmed that they had been contacted for comment by the OCE. Those staffers include former top adviser Peter Waldron, who has publicly accused the campaign of dubious accounting practices in the past.

In January, Waldron filed a complaint with the Federal Election Commission, claiming that the campaign used cash from a pro-Bachmann PAC to pay staffers, despite FEC rules barring collusion between campaigns and PACs. He also accused the Bachmann campaign of hiding payments to Kent Sorenson, an Iowa state senator and Bachmann's Iowa campaign chair, because of ethics restrictions on paying sitting legislators.

The campaign is also under investigation in Iowa for allegedly stealing a list of Christian homeschoolers for campaign purposes, in violation of campaign laws. A separate civil suit brought by a former staffer over that alleged theft is also pending.

According to Politico, the OCE investigation is in its second stage. If OCE investigators vote to send the case to the House for consideration, the Ethics Committee will have 90 days to decide whether to proceed with the investigation and make the OCE's findings public.