The FBI is investigating whether a top Russian banker with ties to the Kremlin illegally funneled money to the National Rifle Association to help Donald Trump win the presidency, two sources familiar with the matter have told McClatchy.

FBI counterintelligence investigators have focused on the activities of Alexander Torshin, the deputy governor of Russia’s central bank who is known for his close relationships with both Russian President Vladimir Putin and the NRA, the sources said.

It is illegal to use foreign money to influence federal elections.

It’s unclear how long the Torshin inquiry has been ongoing, but the news comes as Justice Department Special Counsel Robert Mueller’s sweeping investigation of Russian meddling in the 2016 election, including whether the Kremlin colluded with Trump’s campaign, has been heating up.

All of the sources spoke on condition of anonymity because Mueller’s investigation is confidential and mostly involves classified information.

A spokesman for Mueller’s office declined comment.

Disclosure of the Torshin investigation signals a new dimension in the 18-month-old FBI probe of Russia’s interference. McClatchy reported a year ago that a multi-agency U.S. law enforcement and counterintelligence investigation into Russia’s intervention, begun even before the start of the 2016 general election campaign, initially included a focus on whether the Kremlin secretly helped fund efforts to boost Trump, but little has been said about that possibility in recent months.

The extent to which the FBI has evidence of money flowing from Torshin to the NRA, or of the NRA’s participation in the transfer of funds, could not be learned.

However, the NRA reported spending a record $55 million on the 2016 elections, including $30 million to support Trump – triple what the group devoted to backing Republican Mitt Romney in the 2012 presidential race. Most of that was money was spent by an arm of the NRA that is not required to disclose its donors.

Two people with close connections to the powerful gun lobby said its total election spending actually approached or exceeded $70 million. The reporting gap could be explained by the fact that independent groups are not required to reveal how much they spend on Internet ads or field operations, including get-out-the-vote efforts.

During the campaign, Trump was an outspoken advocate of the Second Amendment right to bear arms, at one point drawing a hail of criticism by suggesting that, if Clinton were elected, gun rights advocates could stop her from winning confirmation of liberal Supreme Court justices who support gun control laws.

“If she gets to pick her judges, nothing you can do folks,” Trump said at a rally in August 2016. “Although the Second Amendment people, maybe there is, I don’t know.”

Spanish authorities tag Torshin for money laundering

Torshin, a leading figure in Putin’s party, has been implicated in money laundering by judicial authorities in Spain, as Bloomberg News first revealed in 2016. Spanish investigators alleged in an almost 500-page internal report that Torshin, who was then a senator, capitalized on his government role to assist mobsters laundering funds through Spanish properties and banks, Bloomberg reported

A summary obtained by McClatchy of the still-secret report links Torshin to Russian money laundering and describes him as a godfather in a major Russian criminal organization called Taganskaya.

Investigators for three congressional committees probing Russia’s 2016 operations also have shown interest in Torshin, a lifetime NRA member who has attended several of its annual conventions. At the group’s meeting in Kentucky in May 2016, Torshin spoke to Donald Trump Jr. during a gala event at the group’s national gathering in Kentucky in May 2016, when his father won an earlier-than-usual NRA presidential endorsement.

An FBI spokesman declined to comment on the investigation.

The NRA did not immediately respond to requests for comment.

Torshin could not be reached for comment, and emails to the Russian central bank seeking comment from Torshin and the bank elicited no response.

Mueller’s investigation has been edging closer to Trump’s inner circle. This week, The New York Times reported that Mueller had negotiated an agreement under which Steve Bannon, who was recently ousted from his post as a senior White House adviser, would fully respond to questions about the Trump campaign. Bannon headed the campaign over its final weeks.

Since taking over the investigation last May, Mueller has secured guilty pleas from two former Trump aides, former National Security Adviser Michael Flynn and former campaign foreign policy adviser George Papadopoulos, both of whom agreed to cooperate with prosecutors; and criminal charges against two other top campaign figures, former campaign Chairman Paul Manafort and his deputy, Rick Gates.