The Senate intelligence committee has asked the National Rifle Association to provide documents on its connections to Russia—including documents related to a 2015 trip some of its top leaders made to Moscow. That’s according to two sources briefed on the committee’s activities.

The NRA did not immediately respond to a request for comment. Spokespersons for Sen. Richard Burr, the intelligence committee chair, and Sen. Mark Warner, the panel’s ranking member, declined to comment on the record.

The NRA’s Russia connections have drawn growing public scrutiny after a key figure in Russian outreach to the powerful gun lobby, Maria Butina, was indicted in July on charges of being an undeclared Russian operative connected to the country’s intelligence apparatus. Butina sought to use guns as a lever to tilt the Republican Party in a pro-Kremlin direction, creating a political firestorm for the NRA in the wake of her arrest. The intelligence committee’s document request is just one part of the aftermath.

Butina, whose Russian political patron Alexander Torshin is a senior figure in the country’s powerful central bank, ran a Russian gun-rights organization called the Right to Bear Arms. In December 2015, the group sponsored an NRA delegation to come to Moscow for a week. NRA dignitaries also met with another influential Russian, the former deputy prime minister Dmitry Rogozin. Torshin subsequently came under U.S. sanctions; Rogozin had been under sanctions since 2014.

Former NRA President David Keene and soon-to-be president Peter Brownell were both on the trip. Accompanying them were Milwaukee Sheriff David Clarke, NRA donors Jim Gregory and Arnold and Hilary Goldschlager, and Jim Liberatore, the president and CEO of the Outdoor Channel.

The intelligence committee isn’t the only Senate panel interested in the trip. The Senate Finance Committee has for months sought NRA documents about the controversial excursion.

Earlier this year, the NRA faced persistent questioning from the Finance Committee over the trip and whether it received money from Russia. The NRA, in a series of letters to the committee, initially denied receiving money from Russia. But in an April 10 letter to Sen. Ron Wyden, its general counsel John Frazer acknowledged receiving “a total of approximately $2512.85 from people associated Russian addresses” and “about $525” from two Russian nationals living in the United States. It also acknowledged “membership dues” from Torshin, a non-voting life member of the NRA since 2012.

“[G]iven the extraordinarily time-consuming and burdensome nature of your requests, we must respectfully decline to engage in this beyond the clear answers we have already provided,” Frazer wrote in April, three months before Butina’s arrest.

The heightened congressional scrutiny of the NRA comes as one of its former top attorneys, William Brewer III, has faced legal challenges of his own.

In September, federal Judge Liam O’Grady chastised the Texas attorney for failing to disclose that a judge in Texas had sanctioned him for more than $133,000 for using an unethical polling practice to influence a jury pool. Brewer challenged that judge’s move, and an appellate court upheld the penalty. The appellate court’s ruling noted that the judge who first sanctioned Brewer found his attitude in that process to be “dismissive and uncaring.”

When Brewer appeared before a Virginia federal court to represent the NRA—in litigation over its “Carry Guard” insurance program for gun owners who shoot people—he asserted that he had not “been reprimanded in any court.” When the judge learned about his prior sanction, he yanked him off the case, as Texas Lawyer detailed.

Brewer has said he didn’t commission the poll, according to Texas Lawyer, and that he neglected to reveal the sanction to O’Grady because he was appealing it to Texas’s highest state court. His firm still represents the NRA.