The Federal Election Commission has slapped the Michigan Democratic Party with a whopping $500,000 fine after the commission ruled the party had underreported cash contributions at bingo fundraisers by $4.4 million.

The Detroit News reported that the party has misreported over 12,000 contributions in the 14 years it ran the fundraisers and violated campaign finance laws, leading to one of the largest ever fines by the FEC after the commission inquired about the bingo events in 2014.

The former head of the Michigan Democratic Party said he initiated an internal probe into the events, which predated his time as chairman, after the request from the commission.

“In the investigation of that inquiry, we discovered the bingo operation was not in compliance,” Johnson told the News. “We shut it down immediately. We investigated and turned over what we found.”

However, not all Democrats were happy with the probe. Former chairman Mark Brewer, who ran the party from 1995 to 2013, described the probe as “an inquisition full of fiction,” claiming party staff were defamed and denied due process

The FEC investigation found that the Democrats had accepted anonymous cash contribution, understated contributions, and reported false contributions and refunds, according to the News.

The Detroit Free Press noted that the fine could have been as much as several million dollars, but the negotiations and the party’s co-operation helped lower the fine.

The local Republican Party suggested the investigation had found a “systematic mishandling” of funds by their Democratic rivals.

“This is further evidence of the Democrats’ inability to represent anyone, even those willing to invest their hard-earned money. They are a party in total disarray,” spokeswoman Sarah Anderson told the Free Press.

“The magnitude of the fine demonstrates that this is not a simple bookkeeping error. It appears to be a systematic mishandling of funds,” she said.

The Detroit News reported that in addition to the fine, the Democrats must also amend past disclosure reports, identify a treasurer to handle compliance, and retain an independent accounting firm to conduct a review.

Adam Shaw is a politics reporter for Breitbart News based in New York. Follow Adam on Twitter: @AdamShawNY