The search, according to two people familiar with the investigation, appeared to be focused on material that Mr. Trump had brought with him to Mar-a-Lago, his private club and residence, after he left the White House. Those boxes contained many pages of classified documents, according to a person familiar with their contents.
Mr. Trump delayed returning 15 boxes of material requested by officials with the National Archives for many months, only doing so when there became a threat of action being taken to retrieve them.
Mr. Trump was known throughout his term to rip up official material that was intended to be held for government archives.