Bernie Sanders ardently supports campaign finance reform, but now he’s literally making it an issue in the Democratic primary, calling the Democratic National Committee’s joint fundraiser with Hillary Clinton a violation of the law.

The Sanders campaign sent a letter to DNC Chairwoman Debbie Wasserman Schultz on Monday alleging that the Hillary Victory Fund has “reported receiving several individual contributions in amounts as high as $353,000 or more, which is over 130 times the $2,700 limit.”

The Hillary Victory Fund is the joint fundraising committee created by the DNC and Hillary for America (HFA).

Nearly 90 percent of Americans want major campaign finance reforms enacted http://t.co/xj6bgbIFNXpic.twitter.com/MRrDb4ZdVM — RT America (@RT_America) June 3, 2015

The letter, which was penned by Bernie 2016’s counsel, Brad C. Deutsch, accused the Hillary Victory Fund of using finances generated by the joint committee, HFA, for advertisements that only appeared to benefit HFA and not the DNC or any smaller state party committees.

The limit that they are referring to is the maximum that the Clinton campaign can accept from each individual donor. If a donor is feeling particularly generous, they can give up to $358,000 to a joint fundraising committee, so if the Hillary Victory Fund has been keeping more than $2,700 donated to the joint committee, then they are indeed in violation of campaign finance laws.

A press release on Sanders’ website explains the matter as follows:

“Unlike Clinton’s presidential campaign committee, Hillary for America, the joint committee may accept large donations of up to $356,100. The first $2,700 of this amount is eligible for transfer to the Clinton campaign, $33,400 can be transferred to the DNC, with any remaining amount, up to $10,000, to each participating state party.”

It then goes on to point out, “According to public disclosure reports, however, the joint Clinton-DNC fund, Hillary Victory Fund (HVF), appears to operate in a way that skirts legal limits on federal campaign donations and primarily benefits the Clinton presidential campaign.”

This is not the first time that Hillary Clinton’s campaign finances have been called into question. In February, the Washington Post raised the issue, saying “[campaign officials for Hillary Clinton] urged state officials to sign on to an ambitious fundraising endeavor that would allow Clinton’s presidential bid, the DNC and the state parties to scoop up and share big checks from wealthy donors.” They also found that because 32 state parties had agreed to join the fund, the committee was allowed to raise donations in amounts 130 greater than an individual could give to Clinton’s campaign.

However, Clinton’s campaign denied any wrongdoing in February, telling the Washington Post that “their use of the fund is proper and that the state parties will benefit from the millions of dollars the joint fundraising committee is generating for the DNC.”

Hillary Sanders? Clinton singing Bernie’s tune on banks, campaign finance https://t.co/MSfrJ9hbMXpic.twitter.com/D1d0IdV455 — RT America (@RT_America) February 11, 2016

The letter also accused the Clinton campaign committee of spending $2.6 million to “reimburse” Clinton’s presidential campaign members for time running the joint committee.

“While the use of joint fundraising agreements has existed for some time — it is unprecedented for the DNC to allow a joint committee to be exploited to the benefit of one candidate in the midst of a contested nominating contest,” said Jeff Weaver, Sanders’ campaign manager, in a news release.

Meanwhile, Tuesday’s Democratic primary in New York looms on the horizon. Time will only tell if the Hillary Victory Fund’s mysterious campaign finances will pay off.