In late November 2021, as officials at the National Archives were trying to persuade former President Donald J. Trump to return a trove of records he had taken from the White House when he left office, one of Mr. Trump’s associates advised him in the sharpest terms possible to give the materials back, newly unsealed documents show.
“Whatever you have, give everything back — let them come here and get everything,” the unnamed associate told Mr. Trump, according to an interview the person gave the F.B.I. “Don’t give them a noble reason to indict you, because they will.”
Less than two years later, that admonition proved prescient. Federal prosecutors charged Mr. Trump last June with violating the Espionage Act, accusing him of illegally holding onto more than 30 highly classified documents and obstructing the government’s repeated efforts to retrieve them.
A summary of the associate’s interview with federal agents was among nearly 400 pages of investigative records that were unsealed on Monday by the judge overseeing Mr. Trump’s classified documents case. The associate’s identity was redacted from the summary.
The records had initially been attached as sealed exhibits to a motion Mr. Trump’s lawyers had filed in January asking for additional discovery evidence from the government. But the judge, Aileen M. Cannon, made the exhibits public after ruling two weeks ago that prosecutors could remove from them the names of several potential witnesses to protect their identities and safety.
The unnamed associate who warned Mr. Trump about the threat of an indictment — identified in the unsealed records as Person 16 — described approaching the former president in a card room or library at Mar-a-Lago, his private club and residence in Florida, as Mr. Trump was dressed in golf attire.
Person 16 told the F.B.I. that Mr. Trump reacted to his warning with a “weird ‘you’re the man’ type of response” and left the impression that he would in fact return the materials to the archives. Their conversation was interrupted when a Mar-a-Lago club member and a “much younger woman” walked up, Person 16 recalled, and asked to have a photo taken with Mr. Trump.
Person 16 also suggested that some of Mr. Trump’s children had been enlisted in the task of persuading him to return the presidential records to the archives. The person recounted to the F.B.I. that one of the children was told: “There are issues with the boxes. They belong to the government. Talk to your dad about giving them back. It’s not worth the aggravation.”
While the unsealed exhibits did not greatly alter the basic story of the classified documents case, they did provide a few new details.
Some of the exhibits revealed, for instance, that the F.B.I. used the code name “Plasmic Echo” for its initial investigation of the classified documents that Mr. Trump took to Mar-a-Lago.
Another exhibit contained a minute-by-minute timeline of the F.B.I.’s search of the property in August 2022, about a year before the indictment was returned, documenting precisely when agents entered the estate, when they gained access to Mr. Trump’s safe “via technical means” and when evidence seized during the search arrived at the Fort Lauderdale airport for transport to Washington.
Another exhibit suggested that the bureau at one point discussed doing “loose” surveillance of Mr. Trump’s airplane to “determine if any boxes are loaded onto the plane.”
But Person 16’s interview with the F.B.I. was among the most informative of the unsealed records. The person asked the agents not to record their conversation, concerned that any recording would be a “risk for him in the Trump world.”
Still, Person 16 was exceptionally candid with the F.B.I., giving his interviewers gossipy details about members of Mr. Trump’s legal team.
One of the lawyers, according to the interview, was brought on board after being seen by Mr. Trump on television. Another member of the team was hired by Mr. Trump, Person 16 said, because of how they “dressed” and by placing themselves directly into Mr. Trump’s “line of sight.”
Person 16 also suggested to the F.B.I. that Mr. Trump may have told his personal aide, Walt Nauta, who was ultimately charged as a co-defendant in the case, that he would receive a pardon if Mr. Trump was elected again.
“Nauta was also told that even if he gets charged with lying to the F.B.I., FPOTUS” — an abbreviation for former president of the United States — “will pardon him in 2024.”
Judge Cannon still has not issued a decision on the underlying motion to which the newly unsealed exhibits were attached.
The motion is an attempt by Mr. Trump’s lawyers to persuade the judge to grant them access to communications between prosecutors working for the special counsel, Jack Smith, and officials at the archives and at national security and intelligence agencies. The lawyers want that information to bolster their potential trial defense that members of the so-called deep state conspired with the Biden administration to have the indictment filed against Mr. Trump.