Eventually, the Justice Department obtained a grand jury subpoena for documents with classification markings remaining in Mr. Trump’s possession, and a lawyer for Mr. Trump turned over several more and told the department there were none left. But an August search by the F.B.I. found 103 more marked as classified — along with thousands of other official records.
The search warrant affidavit that the Justice Department submitted suggested that Mr. Trump was under investigation for obstruction, along with possible violations of the Espionage Act, which criminalizes the willful unauthorized retention of national security documents and failure “to deliver them on demand” to a government official entitled to take custody of them.
Still, whatever the legal questions, as a matter of political reality, the discovery will make the perception of the Justice Department potentially charging Mr. Trump over his handling of the documents more challenging. As a special counsel, Mr. Smith is handling that investigation, along with one into Mr. Trump’s efforts to overturn the 2020 election results and the Jan. 6 attack on Congress, under Mr. Garland’s supervision.
Moreover, the discovery will fuel the fires on Capitol Hill, where Republicans who have just taken the House majority were already planning multiple investigations of the Biden administration, including the decision to have the F.B.I. search Mar-a-Lago.
Representative James R. Comer, the Kentucky Republican who is in line to become the chairman of the House Oversight Committee, said on Monday that he would investigate the discovery of the classified documents in Mr. Biden’s office, vowing to send letters demanding information within 48 hours.
“How ironic,” Mr. Comer said in an interview. “Now we learn that Joe Biden had documents that are considered classified. I wonder, is the National Archives going to trigger a raid of the White House tonight? Or of the Biden Center?” He added, “So now we’re going to take that information that we requested on the Mar-a-Lago raid, and we’re going to expand it to include the documents that Joe Biden has.”
The top Democrat on the committee, Representative Jamie Raskin of Maryland, downplayed the matter, saying that he had confidence that Mr. Garland had taken appropriate steps to review the circumstances and that Mr. Biden’s lawyers “appear to have taken immediate and proper action” to notify the archives of the documents.