Trump lawyers say Mar-a-Lago boxes contained foreign leader briefings

But the 10-page letter that was sent to the House and Senate intelligence committees also revealed the order in which the documents were placed, as well as their contents, inside 15 boxes the National Archives struggled to retrieve for months and precipitated the criminal investigation.

The request was granted several weeks later, and Parlatore and Trusty went to one of the top floors in the main National Archives building overlooking the National Mall and started going through the boxes, which they found preserved just as when Trump had sent them up from his Mar-a-Lago resort.

The boxes, according to the letter, contained a mixture of documents from the White House that were grouped by date and included newspapers, magazines, notes, letters and daily presidential schedules.

Left unsaid was that the criminal investigation has evolved since the initial referral.

Last month, Corcoran was ordered by a senior US judge to testify and hand over his notes to the grand jury hearing evidence in the case, piercing his attorney-client privilege protections through the crime-fraud exception because Trump might have used his advice in furtherance of a crime.

The special counsel is also investigating whether Trump violated the Espionage Act, and prosecutors have recently asked witnesses whether Trump ever showed a map to donors or a book author, a person familiar with the matter said.