The FBI has obtained secret wiretaps collected by Spanish police of conversations involving Alexander Torshin, a deputy governor of Russia’s Central Bank who has forged close ties with U.S. lawmakers and the National Rifle Association, that led to a meeting with Donald Trump Jr. during the gun lobby’s annual convention in Louisville, Ky., in May 2016, a top Spanish prosecutor said Friday.

José Grinda, who has spearheaded investigations into Spanish organized crime, said that bureau officials in recent months requested and were provided transcripts of wiretapped conversations between Torshin and Alexander Romanov, a convicted Russian money launderer. On the wiretaps, Romanov refers to Torshin as “El Padrino,” the godfather.

“Just a few months ago, the wiretaps of these telephone conversations were given to the FBI,” Grinda said in response to a question from Yahoo News during a talk he gave at the Hudson Institute, a conservative think tank in Washington. Asked if he was concerned about Torshin’s meetings with Donald Trump Jr. and other American political figures, Grinda replied: “Mr. Trump’s son should be concerned.”

The comments by Grinda were the first clear sign that the FBI may be investigating Torshin, possibly as a part of special counsel Robert Mueller’s probe into Russian interference in the 2016 U.S. presidential election. Torshin — a close political ally of Vladimir Putin — had multiple contacts with conservative activists in the United States during the election, seeking to set up a summit between the Russian president and then candidate Trump. Although the summit never transpired, Torshin did meet briefly with the president’s son at a private dinner in Louisville during the May 2016 annual convention of the NRA. A member of the NRA since 2012, Torshin has been a regular attendee of the group’s conventions in recent years and hosted senior members of the group in Moscow.

Grinda said that the FBI, in its request for the evidence to the Guardia Civil, the Spanish National Police, provided no explanation as to why it was interested in the material and he didn’t ask for one. “I don’t have to ask them why they want this information,” he said. But Grinda added that if Mueller or any other U.S. prosecutor seeks to use the material as part of a court case, they would have to make a second, more formal request to do so to the Spanish government.

Spokesmen for the FBI and Mueller’s office did not respond to requests for comment. Alan Futerfas, a lawyer for Trump Jr., said he was in a meeting and was unable to comment when contacted by Yahoo News.

Torshin has been the subject of intensifying U.S. government and congressional scrutiny over the past year and was recently among a lengthy list of oligarchs and Russian political figures sanctioned by the Treasury Department.  As reported by Yahoo News and the Spanish newspaper El País last year, the Spanish National Police were preparing to arrest Torshin in August 2013, when he was expected to fly to the Spanish island of Mallorca in August for the birthday party of Romanov. The arrest plan, which involved the deployment of more than a dozen police officers at the airport and at the hotel where the party was supposed to take place, grew out of a lengthy investigation headed by Grinda into Russian organized crime and money laundering. As part of the probe, the Guardia Civil wiretapped Romanov’s phone and picked up 33 conversations with Torshin.

But Torshin never showed up for the party and he was never arrested. Grinda confirmed in an interview after his talk that some in the Guardia Civil suspected that Torshin had been tipped off to the arrest plan by Russian officials who had been asked to cooperate in the Spanish probe. But Grinda added that he was unable to prove that was why Torshin never showed up for the party.