The National Rifle Association is acknowledging that it accepts donations from foreign entities, and that it moves money between its various accounts “as permitted by law.”

The gun group insists it has never received foreign money in connection with an election. But campaign finance experts say that, since money is fungible, that assurance doesn’t mean much.

Though it’s a long way from being confirmed and may never be, the NRA’s new admissions offer perhaps the most compelling evidence yet that foreign money could have allowed the group to conduct political activities boosting Trump.

The admissions came in a recent letter to Sen. Ron Wyden (D-OR), who has sought answers about the group’s foreign funding, following reports that the FBI is probing whether a Russian banker funneled money to the NRA to benefit the Trump campaign.

“While we do receive some contributions from foreign individuals and entities, those contributions are made directly to the NRA for lawful purposes,” NRA General Counsel John Frazer wrote to Wyden. “Our review of our records has found no foreign donations in connection with a United States election, either directly or through a conduit.”

The NRA is not required to disclose how funds are transferred between its various entities. As TPM has reported, that makes it difficult to trace if the NRA legally received foreign money into its general accounts, then transferred the same amount into an account that can be used for political spending.

“Even if the NRA segregated the foreign money that it received, money is fungible,” Brendan Fischer, a campaign finance expert at the Campaign Legal Center, told TPM. “Foreign money in one account frees up money that can be used for elections in another account.”

“This is a very carefully worded letter that appears designed to give the impression that the NRA does not take foreign money for its election work, but reading between the lines, it does not actually say that,” Fischer added. “The NRA said it did not receive foreign money in connection with the U.S. election. It does not say that foreign money was not used in a U.S. election.”

Paul S. Ryan, Vice President of Policy and Litigation at good-government group Common Cause told TPM that the system described in the gun organization’s letter means that “foreign money subsidizes the NRA’s U.S. political spending.”

In his letter, Frazer told Wyden that some donations received between 2015 and 2016 came from U.S. subsidiaries of foreign companies, but none were “connected with Russia, and none of their contributions were made in connection with U.S. elections.”

Campaign finance experts said that the Federal Election Commission would probably allow this system to slide, as long as the NRA was able to demonstrate it was using proper accounting measures to try to ensure that its political expenditures did not come from foreign nationals.

But other investigative bodies might have access to additional evidence that could determine how Russia or other foreign entities wanted their money to be spent. The FBI is reportedly investigating whether Russian banker and lifetime NRA member Aleksandr Torshin channeled money to the group with the express purpose of helping Donald Trump win the 2016 presidential race.

“Presumably they have emails, correspondence, communications,” said the Campaign Legal Center’s Fischer.

A liberal advocacy group has filed a complaint with the FEC requesting an investigation into links between the NRA and Russia.

In the meantime, Wyden’s office is continuing to press the gun lobbying giant for answers.

In a follow-up letter sent Tuesday, Wyden asked Frazer for an in-depth account of how foreign donations were used over the past thee years, and whether Russian nationals were members of the NRA’s donor programs, among other questions.

One issue of interest to Wyden: how the organization makes “transfers between accounts are made as permitted by law,” as Frazer acknowledged it does.

Read the senator’s latest letter below:

This post has been updated.