EXCLUSIVE: Republican leaders on the House Natural Resources Committee are probing the League of Conservation Voters (LCV) over the high-profile eco group's relationship with foreign donors as part of a broader investigation.

Natural Resources Committee Chairman Bruce Westerman, R-Ark., and Rep. Paul Gosar, R-Ariz., the chairman of the panel's oversight subcommittee, penned a letter Tuesday to LCV President Gene Karpinski, demanding answers to a series of questions about his organization's internal operations. The lawmakers particularly questioned whether LCV is in compliance with the Foreign Agents Registration Act (FARA).

The letter noted that LCV is registered to lobby on policies within the committee's jurisdiction — the group opposes fossil fuel drilling on public lands and pushes green energy policies — but has received millions of dollars in contributions from Hansjörg Wyss, a Swiss billionaire. Under FARA, individuals and organizations financed by a foreign principal or which lobby for a foreign principal must register to do so.

"The Committee is concerned that LCV's relationship with foreign donors, such as Swiss national Mr. Wyss, who are prohibited from contributing, either directly or indirectly, to domestic political campaigns, may impact LCV's political and lobbying activities relating to America's ability to achieve energy independence," Westerman and Gosar wrote in the letter first obtained by Fox News Digital. 

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House Natural Resources Chairman Bruce Westerman (R-AR) speaks at a press conference following a House Republican meeting at the U.S. Capitol on March 28, 2023 in Washington, DC. The Republicans met to discuss their new energy plan which would increase domestic energy production and eases environmental review on energy and mining projects. (Photo by Kevin Dietsch/Getty Images)

House Natural Resources Chairman Bruce Westerman, R-Ark., speaks at a press conference at the Capitol on March 28. (Kevin Dietsch/Getty Images)

"As you are aware, such political and lobbying activities may require compliance with FARA," the GOP lawmakers continued in the letter. "The central purpose of FARA is to ‘promote transparency with respect to foreign influence within the United States by ensuring that the United States government and the public know the source of certain information from foreign agents intended to influence American public opinion, policy, and laws.’" 

They added that the law makes registration requirements clear for a person or group "acting in the political or public interests of a foreign government or entity," even when done through intermediaries. FARA registration also includes individuals or entities that conduct several other activities, like public relations and political consulting work, for a foreign principal.

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According to the lawmakers, failing to register under FARA may result in an up to $10,000 fine and a five-year prison sentence.

The oversight into LCV, they said, is part of the committee's broader investigation into "potential manipulation of U.S. tax-exempt organizations" by foreign entities aimed at influencing American environmental, natural resource and energy policy. The probe will take a look at LCV, the LCV Action Fund, LCV Victory Fund and LCV Education Fund.

"Public records show highly unsettling ties between a foreign billionaire and the dark money network that funds the League of Conservation Voters," Westerman told Fox News Digital. "It’s deeply troubling to find any association between unregistered foreign interests and domestic lobbying efforts in our nation’s capitol."

"Even more concerning are the efforts by such groups to limit American energy production and effectively eliminate America’s energy independence," he said. "Unregistered foreign interests have no place in manipulating organizations that influence America’s environmental, natural resources and energy policies, and it’s Congress’ duty to conduct thorough oversight of this situation."

Hansjorg Wyss, a Swiss national, is pictured in New York City for an environmental benefit. (Craig Barritt/Getty Images for Oceana)

Overall, the LCV reported receiving $114.7 million in financial contributions in 2021, a roughly 48% increase compared to the $77.7 million it received in 2020, according to the group's tax filings obtained by Fox News Digital late last year. A large portion of the group's funding has come from the Wyss Foundation and Berger Action Fund, two dark money groups overseen by Wyss.

Additional filings obtained by watchdog group Americans for Public Trust (APT) showed that a single anonymous donor, likely Wyss himself, wired a staggering $278.9 million to the Berger Action Fund between April 2021 and March 2022. The group, in turn, contributed $72.7 million to 12 separate organizations, all of which are involved in political campaigns, including nearly $3.5 million to LCV.

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In addition, the Berger Action Fund funneled $20.3 million to a group called Fund for a Better Future (FBF), the largest donation the fund received that year. FBF then sent nearly $10.7 million to LCV, the most significant contribution FBF gave to any group in 2021.

And the Berger Action Fund sent an additional $42.5 million to the Sixteen Thirty Fund, a key cog in a billion-dollar dark money network. Sixteen Thirty Fund subsequently contributed $18.9 million to LCV.

The Wyss Foundation wired another $60,000 to the LCV in 2021 and $210,000 to the LCV Education Fund in 2020.

Molly McUsic, who sits on LCV's board of directors is also the president of Wyss Foundation and a director on the board of the Berger Action Fund.

Gulf oil

The League of Conservation Voters has been a vocal opponent of oil and gas drilling on public lands and in federal waters. (AP Photo/Dario Lopez-Mills, File)

"The Berger Action Fund and Wyss Foundation are committed to complying with all rules governing their activities and have established strict policies prohibiting their funds from being used for get-out-the-vote activities, voter registration, or supporting or opposing political candidates or parties," a spokesperson for the Berger Action Fund and Wyss Foundation told Fox News Digital in April.

"Berger’s grants to the Sixteen Thirty Fund and Fund for a Better Future supported advocacy, including for the Inflation Reduction Act, which lowers prescription costs, expands access to health care, invests in clean energy, and closes tax loopholes," they continued. "This funding also supported advocacy around the Bipartisan Infrastructure Law to ensure the final legislation contained significant investments in climate and green infrastructure."

Fox News Digital reported at the time that LCV Victory Fund, the group's political action committee, and another group Climate Power hired BlueLabs Analytics, a Washington, D.C.-based data science organization, to mine data of more than two million of President Biden's voters in crucial swing states with advertisements and mailers ahead of the 2022 midterm elections.

Experts raised concerns that the operation, and other similar funding schemes for political activity potentially tied to Wyss, may violate federal statute given his nationality.

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"Swiss billionaire Hansjorg Wyss spent nearly $73 million to influence American politics and policy, routing most of that money through the Arabella Advisors network," Caitlin Sutherland, APT's executive director, told Fox News Digital. "Without offering any evidence, Mr. Wyss’ groups insist that his foreign money does not end up in partisan electoral activities." 

"But now we have proof that the climate groups he funds funneled money to specifically target Biden voters in key states," she continued. "This dangerous pattern of giving by the left’s largest foreign mega-donor warrants immediate congressional oversight."

In a statement, LCV said it had received the letter, but that it complies with all laws.

"LCV and related entities comply fully with the law. We will review the letter to determine our appropriate response," the group told Fox News Digital.