The Campaign Legal Center, one of Washington’s top election spending watchdogs, filed a formal complaint Monday morning with the Federal Election Commission asserting that there is “reason to believe” that the National Rifle Association violated campaign finance laws in four key Senate races in the 2014 and 2016 election cycles. The Legal Center is asking the regulator to conduct an “immediate investigation” of the NRA’s election activities, and seek “appropriate sanctions.”

“There is substantial evidence that the NRA funneled millions through a shell corporation to unlawfully coordinate with candidates it was backing,” Brendan Fischer, the director of the Legal Center, said in a press release.

The Legal Center’s complaint is based on an investigation published on July 13 by The Trace and Politico Magazine, which details the gun group’s relationship with its top election contractor, Starboard Strategic Inc. The vendor began appearing in the NRA’s campaign finance reports during the 2014 election cycle, and shares offices and leadership with the election communications and ad firm OnMessage Inc., which has worked for Senate candidates in campaigns in which the NRA has also been active.

All told, the NRA has paid Starboard more than $60 million to try to sway federal elections. Other than the NRA spending, FEC records show a small single payment — less than $20,000 — from one other client, the National Republican Senate Committee.

“This report raises troubling new questions about whether the NRA and its consultants were illegally funneling dark money through a shell company,” said Senator Ron Wyden, an Oregon Democrat. “The FEC should thoroughly investigate whether Starboard was created as an end-run around federal election laws.”

If the FEC proceeds with an inquiry and concludes that the NRA’s conduct was unlawful, the gun group could face steep fines.

The Trace and Politico’s investigation found no clear or meaningful distinction between Starboard and OnMessage Inc. The partners at OnMessage established Starboard in 2013, in advance of the coming elections. In addition to shared officers and addresses, internal emails indicate executives toggled between roles for both the firms. An ex-employee of OnMessage, who requested anonymity out of a fear of professional reprisals, could not remember Starboard having its own staff, or other distinct presence. “I don’t recall anything within our office that was called or associated with Starboard,” the former employee said, “beyond some Starboard-labeled thumb-drives.”

During the 2014 election cycle, OnMessage served as the top campaign consultant to three Republican Senatorial candidates: Thom Tillis, in North Carolina; Tom Cotton, in Arkansas; and Cory Gardner, in Colorado. Each was challenging a Democratic incumbent, and each paid the firm between $5 million and $8 million dollars.

During those same races, the NRA paid Starboard for ads in support of those candidates, all of whom ultimately won election.

A similar arrangement played out in 2016, when OnMessage worked for the campaign of Ron Johnson, who was running for Senate in Wisconsin against Russ Feingold, the Democratic incumbent. Johnson, like the others, was victorious.

“The NRA using inside information about a candidate’s strategy to create ‘independent’ ads supporting him creates an unfair advantage, and it violates the law,” said Fisher.

Outside groups like the NRA can independently spend unlimited sums of money to influence elections — but they face strict contribution limits when giving directly to a candidate.

If an outside group and a campaign use the same vendor, then employees working for either client must be prevented from sharing information. Without a firewall in place, any spending by the outside group is no longer independent, and therefore cannot exceed $5,000. The NRA paid Starboard millions for ads in the three key 2014 Senate races, and almost $200,000 for work on the 2016 contest.

After reviewing our findings, two former FEC chairs — Republican Trevor Potter, and Democrat Ann Ravel — independently came to the same conclusion: “The FEC should investigate.” The complaint by the Campaign Legal Center could lead to such an inquiry. The next step will be for the commission to ensure that the complaint meets the appropriate legal standards. If so, the agency will then give the NRA a chance to respond.

The NRA did not respond to a request for comment, and has ignored both interview requests and written questions seeking information on its use of Starboard in high-priority elections. OnMessage also did not respond to an inquiry about the watchdog’s complaint.