A group known to be a “dark money ally” of Democratic presidential candidate Hillary Clinton has filed ethics complaints with the Federal Election Commission (FEC) against her opponent, Bernie Sanders.

Clinton’s ally specifically alleges Sanders failed to disclose who paid for a “sponsored” advertisement, which appeared on Facebook after the New Hampshire Democratic primary. It filed a complaint against Sanders campaign treasurer, Susan Jackson, for allegedly accepting “excessive contributions” from individuals. Most strikingly, a complaint against National Nurses United and “People for Bernie” was filed as well.

The complaints were made by the American Democracy Legal Fund (ADLF), which was founded by David Brock, whose fingerprints have been on many of the dishonest attacks against Sanders during the 2016 election.

The latest Clinton campaign has pioneered what Bloomberg described as “the outsourcing of routine campaign functions to outside groups that are permitted to raise money in unlimited amounts.” This kind of unprecedented coordination has unfolded between the Clinton campaign and another one of Brock’s super political action committees, Correct the Record.

Correct the Record is a spin-off from American Bridge 21st Century, another Brock super PAC. It receives money from a 501(c)4 foundation which does not have to disclose how it is funded.

According to the Sunlight Foundation, which promotes transparency in politics, these groups are part of a network of “dark money allies” of the Clinton campaign.

Both National Nurses United and “People for Bernie” have made valuable contributions to the Sanders campaign. Dues-paying nurses in the prominent nurses union have financed mailers, phone calls to voters, canvassing, and bus tours in primary states. “People for Bernie,” a project of Progressive Kick, has built up a social media following and a network of websites, Twitter handles, and Facebook pages to inspire citizens to volunteer for the Sanders campaign.

National Nurses United and Progressive are using super PACs to help boost the Sanders campaign. What ADLF alleges is the union has openly coordinated activity with the Sanders campaign and held “joint events” and trained nurses associated with the union.

The Clinton ally also alleges the same type of coordination between “People for Bernie” and the Sanders campaign:

In July 2015, the founder of People for Bernie said he was in contact with Bernie 2016. In fact, the campaign provided buttons and posters for People for Bernie to use in the New York City Gay Pride Parade. The campaign has also asked People for Bernie to promote campaign events. Marcus Ferrell, the African American outreach director of Bernie 2016, participated on a conference call addressing structural racism co-sponsored by People for Bernie. Additionally, after a recent campaign event where Carlos Rojas-Alvarez, a coordinator for the Student Immigration Movement, and Patty Healy, from the National Nurses United union, introduced Senator Sanders, People for Bernie emailed Carlos Rojas-Alvarez with the video of the event.

To some extent, Brock’s group is deliberately creating a false equivalency between the work of a nurses union and a progressive activism group, and the alliance of super PACs propelling Clinton’s presidential campaign. Yet, one reason why this is a tough sell is because a group like Priorities USA Action (a prominent Clinton-allied super PAC) was 98 percent funded by donations of $100,000 or more in the second half of 2015. Ninety percent of the funds were donations that were over $1 million.

This simply is not the case for a nurses union or a progressive activism group. The National Nurses United PAC had a little over $43,000 on hand at the end of 2015. Meanwhile, Priorities USA Action had $35.8 million at the end of 2015.

Stunningly, this is an attack on a labor union for its role in boosting a progressive politician’s campaign. It is the kind of attack one might expect from a right-wing group like Crossroads GPS, founded by Karl Rove.

Additionally, this is a calculated attempt by Brock’s group to ensnare the Sanders campaign’s resources in a time-consuming effort to defend two key groups, which have played significant roles in mobilizing voters in the Democratic primary. It also is an effort to damage Sanders’ brand as a politician setting an example for how to run a successful and ethical campaign in a post-Citizens United world.

The American Democracy Legal Fund has focused primarily on Republican opponents. As the Sunlight Foundation notes, in October, the group filed a complaint against Jeb Bush’s super PAC, Right to Rise, and alleged the campaign and super PAC were engaged in “illegal coordination.”

It is difficult not to view this as hypocritical. There are limited disclosures about funds to ADLF, but the 527 committee received $50,000 from American Bridge. This super PAC has received $3.7 million from the American Bridge 21st Century Foundation since 2014. All the donors to the Bridge foundation know their names will not be disclosed.

According to records examined by the Sunlight Foundation, the same big donors, which fund American Bridge, are also funding Correct the Record, which has stretched the legal boundaries of what coordination is allowed between a candidate’s campaign and a super PAC.

During the second half of 2015, Priorities USA Action donated $1,000,000 to Correct the Record. American Bridge 21st Century donated $50,000. Hillary For America contributed the most money to Correct the Record in the first half of 2015. The Clinton campaign’s donation was for “research services.”

Brad Woodhouse, the co-founder of ALDF, is also the president of Correct the Record. He was previously the head of the American Bridge super PAC.

If it all seems incestuous, that is because individuals like Brock and Woodhouse are able to move from one group to another as the Clinton campaign desires.

Paul Ryan, a lawyer at the Campaign Legal Center, who considered filing complaints with the FEC and Justice Department challenging the group’s “novel legal theories,” told Time.com, “[Correct the Record] is creating new ways to undermine campaign regulation.”

As of February 1, Brock was drawing a paycheck from the American Bridge super PAC while he was coordinating with the Clinton campaign through Correct the Record, something which he should be legally prohibited from doing.

What is remarkable is Correct the Record defends its coordination with the Clinton campaign by arguing “the online-only nature of its work—as opposed to broadcast communications or other paid media—allows it to legally coordinate with the campaign.” And yet, Brock’s group is going after the “online-only” activities of “People for Bernie.”

Jeff Weaver, a campaign manager for Sanders, told MSNBC on March 30, “Just one day after the Clinton campaign said we needed to change our tone, the leaders of their coordinated super PAC, which is funded by millions from Wall Street, filed baseless and frivolous complaints with the FEC. Tells you all you need to know.”

Currently, the complaints have received minimal media attention, which is probably what the Clinton campaign hopes. If the press allows the FEC to quietly go after the Sanders campaign based on Brock’s complaints without talking about it too much, the Clinton campaign will not have to worry about being pulled into a debate about the ethics of their fundraising through Brock and a network of “dark money allies.”