The N.R.A. would not say why the circuitous 2016 payments had been structured that way, but more than half of the money was used to reimburse the travel costs of one member of the delegation, David A. Clarke, Jr., who was then sheriff of Milwaukee. His public ethics form listed Mr. Brownell, not the N.R.A., as having financed a Russia trip.

The payments have troubled some in the N.R.A.’s orbit, and led to contentious debates within the organization earlier this year. Mr. Brewer argued in a series of internal presentations that those involved had exposed themselves to wire fraud charges, a contention that other lawyers advising the organization found to be meritless. But some worry that the payments could pose problems for the N.R.A. in an investigation by New York Attorney General Letitia James, whose office is examining whether the organization violated laws relating to its tax-exempt status and has taken a particular interest in how donor funds are spent.

Information about the payments has also been turned over in congressional inquiries.

“These financial transactions were examined during the course of the investigation and are of ongoing interest,” said an aide to Senator Ron Wyden of Oregon, the ranking Democrat on the Finance Committee, who has been leading an investigation into the N.R.A. The aide spoke on the condition of anonymity because the inquiry is ongoing.

Mr. Brownell paid the N.R.A. again for the Russia trip in mid-February 2018 — the only reimbursement the group has previously disclosed, and one that it did not refund. That payment was for $17,000. It was not clear why that amount was chosen, and the N.R.A. did not offer an explanation.

But the rationale for the payment was fairly clear. By then, the group faced a budding public relations crisis. News reports had begun to raise questions about the N.R.A.’s ties to Russia, and days earlier, on Feb. 2, Mr. Wyden had sent the N.R.A. a letter seeking information. A note appended to Mr. Brownell’s check by one of his lawyers seemed aimed at broader consumption, noting that the payment was for “the unauthorized trip to Russia.”

Asked this week about the 2016 payments, Mr. Brewer, the outside counsel, said, “Wayne had no awareness of the transactions in question,” adding that “it is a matter of public record that he opposed the trip.” He declined to discuss the legal advice he had provided.

The 2016 transactions were overseen by Millie Hallow, an aide to Mr. LaPierre, according to emails. In one February 2016 email, Ms. Butina sent an invoice directly to Ms. Hallow for “Hosting of NRA leadership group for six days in Moscow,” according to the document, and thanked her “for your invaluable advice these past few months.”