Turning on his iPhone one day last year, the lawyer M. Evan Corcoran recorded his reflections about a high-profile new job: representing former President Donald J. Trump in an investigation into his handling of classified documents.
In complete sentences and a narrative tone that sounded as if it had been ripped from a novel, Mr. Corcoran recounted in detail a nearly monthlong period of the documents investigation, according to two people familiar with the matter.
Mr. Corcoran’s narration of his recollections covered his initial meeting with Mr. Trump in May last year to discuss a subpoena from the Justice Department seeking the return of all classified materials in the former president’s possession, the people said.
It also encompassed a search that Mr. Corcoran undertook last June in response to the subpoena for any relevant records being kept at Mar-a-Lago, Mr. Trump’s private club and residence in Florida. He carried out the search in preparation for a visit by prosecutors, who were on their way to enforce the subpoena and collect any sensitive material found remaining there.
Government investigators almost never obtain a clear lens into a lawyer’s private dealings with their clients, let alone with such a prominent one as Mr. Trump. A recording like the voice memo Mr. Corcoran made last year — during a long drive to a family event, according to two people briefed on the recording — is typically shielded by attorney-client or work-product privilege.
But in March, a federal judge ordered Mr. Corcoran’s recorded recollections — now transcribed onto dozens of pages — to be given to the office of the special counsel Jack Smith, who is leading the documents investigation.
The decision by the judge, Beryl A. Howell, pierced the privilege that would have normally protected Mr. Corcoran’s musings about his interactions with Mr. Trump. Those protections were set aside under what is known as the crime-fraud exception, a provision that allows prosecutors to work around attorney-client privilege if they have reason to believe that legal advice or legal services were used in furthering a crime.
Judge Howell, in a sealed memorandum that accompanied her decision, made clear that prosecutors believe Mr. Trump knowingly misled Mr. Corcoran about the location of documents that would be responsive to the subpoena, according to a person familiar with the memo’s contents.
Mr. Corcoran’s notes, which have not been previously described in such detail, will likely play a central role as Mr. Smith and his team move toward concluding their investigation and turn to the question of whether to bring charges against Mr. Trump. They could also show up as evidence in a courtroom if a criminal case is ultimately filed and goes to trial.
The level of detail in the recording is said to have angered and unnerved close aides to Mr. Trump who are worried they contain direct quotes from sensitive conversations.
Mr. Corcoran, who was brought into Mr. Trump’s orbit by a political and legal adviser to the former president, Boris Epshteyn, did not respond to a message seeking comment.
Steven Cheung, a spokesman for Mr. Trump, said in a statement that “the attorney-client privilege is one of the oldest and most fundamental principles in our legal system” and he accused the Justice Department of trying to deny Mr. Trump “this basic right.”
Mr. Cheung added that “whether attorneys’ notes are detailed or not makes no difference — these notes reflect the legal opinions and thoughts of the lawyer, not the client.” And he maintained that Mr. Trump had tried to cooperate when Justice Department officials came to the property in June last year.
In an early scene in his account, Mr. Corcoran describes meeting Mr. Trump at Mar-a-Lago last spring to help him handle a subpoena that had just been issued by a federal grand jury in Washington seeking the return of all classified material in the possession of his presidential office, the people familiar with the matter said.
After pleasantries, according to a description of the recorded notes, Mr. Trump asked Mr. Corcoran if he had to comply with the subpoena. Mr. Corcoran told him that he did.
That exchange could be useful to prosecutors as they collect evidence on whether Mr. Trump sought to obstruct the subpoena process and interfere with the government’s broader efforts to retrieve all of the sensitive records that he took with him from the White House.
But people close to Mr. Trump have said the conversation could be read in a more favorable light as a client merely asking his lawyer about how he should proceed.
The recording also describes how Mr. Corcoran conducted a search of a Mar-a-Lago storage room in an effort to comply with the subpoena’s request for documents, the people familiar with the account said. Mr. Corcoran told a grand jury in May that several employees at the compound had told him everything he needed was being kept in the storage room, located in the basement of the property, according to people with knowledge of the matter.
Mr. Corcoran subsequently handed over to Justice Department officials more than three dozen documents he turned up in his search, and drafted a letter to the department stating that a diligent search had not found any more.
The notes in the recording do not suggest that Mr. Corcoran was waved away from searching anywhere other than the storage room, the people familiar with them said. But they also indicate that no one at Mar-a-Lago — including Mr. Trump — spoke up to tell him that he should look elsewhere.
In the end, it turned out the employees who directed Mr. Corcoran to the storage room were wrong. In August, when F.B.I. agents descended on Mar-a-Lago with a court-approved search warrant, they found classified documents not only in the basement of Mar-a-Lago, but also in Mr. Trump’s office.
The issue of who moved boxes into and out of the storage room — and why — has become one of the central parts of Mr. Smith’s investigation. Prosecutors have focused much of their attention on Walt Nauta, an aide to Mr. Trump who took part in moving boxes, and on another Mar-a-Lago employee, Carlos Deoliveira, a maintenance worker who helped Mr. Nauta.
Mr. Smith’s team has also focused on a related question: whether there were any efforts to interfere with the government’s attempts to obtain security camera footage from Mar-a-Lago that could shed light on how the documents were kept in the storage room and who had access to them. Mr. Corcoran’s notes provide some details about Mr. Nauta’s involvement in the search.
They say, for instance, that Mr. Nauta unlocked the storage room door for Mr. Corcoran, according to the people familiar with them. They also say that Mr. Nauta brought Mr. Corcoran some tape so that he could seal in a folder the classified documents he found, in preparation for giving them to prosecutors.
There is also a reference to Mr. Corcoran’s meeting with the prosecutors, which took place at Mar-a-Lago on June 3 last year. He and another lawyer for Mr. Trump, Christina Bobb, met Jay Bratt, the chief of the counterespionage section of the national security division of the Justice Department, to turn over the documents he found and convey the letter asserting that to the best of their knowledge no more remained at Mar-a-Lago.
The notes refer to Mr. Trump’s appearance related to Mr. Bratt’s visit, according to one person briefed on the contents of the notes.
Judge Howell’s memorandum compelling Mr. Corcoran to answer questions in front of a grand jury and to produce his notes described the lawyer as essentially a casualty of Mr. Trump’s months of gamesmanship with investigators and National Archives officials about returning the documents, according to a person familiar with the memo’s contents.
As The New York Times reported in April, Judge Howell wrote in the memorandum, according to the person familiar with its contents, that Mr. Trump’s earlier actions and “misdirection” of archives officials’ efforts to retrieve what turned out to be more than a dozen boxes of records were a “dress rehearsal” for the May subpoena.