They Are Trump’s Aides and Lawyers. Now They Could Be Trial Witnesses.

Throughout the inquiry into former President Donald J. Trump’s handling of classified material, his insular world at Mar-a-Lago was rife with intrigue, anxiety and competing motives as investigators sought testimony and evidence from his some of his closest aides, advisers, lawyers and even members of his Secret Service detail.

Now, with Mr. Trump under federal indictment and with people who currently, or used to, work for him seen as potential prosecution witnesses, the pressure on those around him — both at Mar-a-Lago in Florida and at his summer residence in Bedminster, N.J. — has only increased.

Mr. Trump is in the position of waging a presidential campaign and preparing a defense at the same time. Complicating matters, he has been forbidden from discussing the latter with a number of people who could presumably help him with the former, some of whom are no doubt wondering who is saying what to the government as they go about their jobs.

In court in Miami on Tuesday, the federal magistrate judge who handled Mr. Trump’s arraignment ordered the former president not to discuss the case with his co-defendant and personal aide, Walt Nauta, saying that any communications about it would have to go through their lawyers.

The judge also made clear that he did not want Mr. Trump talking about the facts in his indictment with any potential witnesses, leading prosecutors to agree to provide him and his lawyers with a further list of people with whom he would have to be careful in conversation.

As was the case with the House select committee’s investigation last year into Mr. Trump’s efforts to retain power after his election loss, much of the evidence in the documents inquiry has come from people in Mr. Trump’s inner circle, underscoring the costs and limits of loyalty to him.

The difficult nature of the situation was made clear at the court proceeding by one of Mr. Trump’s lawyers, Todd Blanche, who argued that the entire case against Mr. Trump was “about what happened at Mar-a-Lago, it’s about what happened at Bedminster.” Trying to bar the former president from interacting with members of his staff, Mr. Blanche went on, was “unworkable.”

To take just one example of the challenges that Mr. Blanche described: Mr. Nauta and his lawyer had joined Mr. Trump for dinner just the night before, according to a person with knowledge of the encounter.

The question of whether Mr. Trump has interfered with witnesses has come up in previous investigations. The inquiry led by the special counsel Robert S. Mueller III examined, among other things, whether Mr. Trump’s Twitter posts declaring that his former lawyer and fixer, Michael D. Cohen, would not flip on him constituted obstruction of justice. (Mr. Trump was not charged.)

During a House select committee investigation into Mr. Trump’s efforts to remain in power after losing the 2020 election, former Representative Liz Cheney, a Wyoming Republican and a leader of the committee, said that Mr. Trump had placed a telephone call directly to a witness.

Throughout the documents investigation, which is being led by the special counsel Jack Smith, many employees at Mar-a-Lago were interviewed about Mr. Trump by Mr. Smith’s team at a time when, like Mr. Nauta, they were being represented by lawyers paid by Mr. Trump’s political action committee.

Some of the lawyers Mr. Trump hired to defend him in the case have also wound up being questioned by the government and may appear as witnesses as well.

The provision that Mr. Trump not discuss the case with potential witnesses could be difficult to enforce, given that Mr. Trump’s speaking style is often ungovernable. It could be especially challenging with regard to Mr. Nauta, whose job is to trail the former president, day in and day out, catering to his every minor need.

Prosecutors under Mr. Smith have agreed to provide a list of potential witnesses to Mr. Trump’s team — though it may be narrowly tailored to avoid revealing too much about their investigation. To that end, David Harbach, a senior prosecutor on Mr. Smith’s team, said in court that it was not likely to be “an exhaustive list” that would place undue burdens on Mr. Trump and the people working for him.

Steven Cheung, a spokesman for Mr. Trump, said of the witnesses who may be called: “The Department of Justice has continually shown a total lack of respect for the rule of law by harassing President Trump, his team, his lawyers, and his supporters.” He said the prosecutors’ move was a “politically motivated attempt to interfere with the 2024 election.”

The indictment filed against the former president last week included some hints on who they might be.

Chief among the possible witnesses mentioned in the indictment is Molly Michael, Mr. Trump’s former assistant, who worked for him in the White House and then went on to work at Mar-a-Lago, according to two people familiar with the matter. Ms. Michael is described as “Trump Employee 2” and appears at several key moments laid out in the charging document.

A lawyer for Ms. Michael did not respond to a message seeking comment.

Prosecutors described a text she sent another employee about how far away from Mr. Trump the boxes should be stored: “Anything that’s not the beautiful mind paper boxes can definitely go to storage,” she wrote in one message. At another point, the indictment says, Ms. Michael took a photograph of boxes before Mr. Trump went through at least some of them in late 2021, as National Archives and Records Administration pressed for their return.

Mr. Trump has been skeptical of Ms. Michael since she left his employ at the end of last summer, according to one person familiar with his thinking. By then, she had been approached multiple times by investigators who had begun their inquiry into the material in the spring, according to the person familiar with the comments.

The indictment also makes reference to “Trump Representative 1,” who was said in the indictment to have sent a message to Ms. Michael in late 2021, searching for an answer about how many boxes Mr. Trump was planning on returning to the archives. That representative was the lawyer Alex Cannon, according to two people familiar with the matter. Mr. Cannon, who no longer works directly for Mr. Trump, declined to comment.

Mr. Cannon was in touch with officials at the archives and repeatedly urged Mr. Trump to return the government records in his possession, according to multiple people familiar with his discussions with the former president. The indictment focuses narrowly on allegations of obstructing the grand jury subpoena for remaining documents, but like others around Mr. Trump, Mr. Cannon could provide a window into that period of time.

The indictment also mentions two lawyers, Trump Attorney 1 and Trump Attorney 2, who told Mr. Trump that they needed to conduct a search to comply with a May grand jury subpoena demanding the return of all classified material in his possession.

Those lawyers are M. Evan Corcoran and Jennifer Little, both of whom were subpoenaed for testimony and records, nearly all of them possessed by Mr. Corcoran, by Mr. Smith’s team during the investigation. According to the indictment, Mr. Trump told Mr. Corcoran that he wanted to be at Mar-a-Lago when Mr. Corcoran did a search, and that Ms. Little did not have to be there.

Mr. Corcoran, in particular, could prove to be a pivotal witness should the case go to trial, given that he recorded extensive audio notes about his dealings with Mr. Trump concerning both the receipt of the subpoena and the search of boxes in a storage room at Mar-a-Lago undertaken in an effort to comply with it.

A federal judge allowed prosecutors to pierce attorney client privilege and obtain testimony and most of Mr. Corcoran’s notes. Several damning excerpts from them were quoted in the indictment, apparently showing Mr. Trump trying to get around the demands set forth in the subpoena.

Mr. Corcoran did not respond to a message seeking comment. Ms. Little declined to comment.

The indictment also mentions a third lawyer — Trump Attorney 3 — who signed an attestation, at Mr. Corcoran’s request, certifying that a “diligent search” of “the boxes that were removed from the White House to Florida” had been conducted and that “any and all responsive documents” had been found.

Prosecutors say the attestation signed by that lawyer, Christina Bobb, was false because Mr. Trump had already directed Mr. Nauta to move several boxes in a way that kept them from being searched.

Ben Protess contributed reporting.