The vice chairwoman of the Federal Election Commission (FEC), who once falsely accused the Koch brothers of campaign finance disclosure violations, will testify on Wednesday before a congressional hearing about anonymous campaign donations.

Ann Ravel will testify at the Senate Rules Committee hearing titled, "Dollars and Sense: How Undisclosed Money and Post-McCutcheon Campaign Finance Will Affect 2014 and Beyond." Ravel was previously criticized for accusing Charles and David Koch of being involved in campaign finance violations in California, a claim she later stated was not true.

The controversy occurred when Ravel was chairwoman of the California Fair Political Practices Commission (CFPPC). A settlement announced last year by the CFPPC required two nonprofits, the Center to Protect Patient Rights (CPPR) and Americans for Responsible Leadership (ARL), to pay $1 million to the state of California for failing to disclose "two dark money independent expenditure contributions in the 2012 election."

The contributions were in opposition to Proposition 30, a tax hike on the wealthy, and in support of Proposition 32, a prohibition on using union dues for political purposes.

The California commission found that CPPR was the source of two contributions worth about $15 million that were improperly reported and that used other nonprofits as intermediaries. The commission’s press release described CPPR as "the key nonprofit in the Koch Brothers' dark money network of nonprofit corporations." Ravel also said at a press conference that the "Koch network" has "tentacles all over the country."

However, Koch Industries vigorously denied Ravel’s accusations and noted that they actually opposed Proposition 32.

"We did not support, either directly or indirectly, this ballot initiative which would have restricted public and private sector employees’ rights to contribute to candidates," the group said in an October statement. "The pronoun ‘we’ refers to Koch Industries and its corporate entities; Charles Koch; David Koch; and their foundations. In addition, we did not give directly or indirectly to any non-profit group in support of this ballot initiative."

Ravel later walked back her comments in a November interview with a local television station. "The Koch brothers have never been implicated themselves as having been direct donors," she said.

The FEC did not respond to a request for comment about Ravel’s testimony at the hearing. She joined the commission in October after receiving an appointment from the Obama administration.

Lawyers and former U.S. Supreme Court Justice John Paul Stevens will also testify at the hearing.

Stevens, now a prominent critic of anonymous campaign donations, actually wrote the majority opinion in a 1995 Supreme Court decision that defended anonymous political speech as a right guaranteed by the First Amendment.

While the Koch brothers typically receive more scrutiny from lawmakers and the media about their donations to conservative groups, the hearing on Wednesday comes amid the annual meeting for the secretive club of wealthy liberals known as the Democracy Alliance.

One of the alliance’s members, San Francisco hedge fund billionaire Tom Steyer, has already pledged to spend $100 million in the upcoming midterm elections on candidates who support environmentalist causes. Steyer is now under fire after public records revealed that his hedge fund was allegedly involved in a Ponzi scheme to defraud German real estate investors of $67 million.