WASHINGTON — Federal authorities are in the preliminary stages of investigating the handling of classified material found at former President Donald J. Trump’s Florida home after he left office, people familiar with the matter said on Thursday.
The effort, led by the F.B.I., stems from the discovery of classified information in 15 boxes that contained documents, mementos, gifts and letters that had been taken from the White House at the end of Mr. Trump’s term in apparent violation of the requirements for turning over all presidential records to the National Archives.
The development was reported earlier by The Washington Post.
The National Archives said in February that it had consulted with the Justice Department about the classified material, which it retrieved the previous month from Mr. Trump’s Mar-a-Lago home in Florida. The agency described the materials in question as “classified national security information.”
The Justice Department has instructed the National Archives not to share with the House Oversight Committee, which is conducting its own investigation, details about the material taken from the White House by Mr. Trump, the committee disclosed on Thursday, in a hint that a criminal investigation might be underway.
In cases of this type, the F.B.I. would typically look at an array of scenarios, including whether the classified material was mishandled or inadvertently disclosed, and it could examine whether a foreign adversary might have gotten access.
The investigation could put Mr. Trump at odds with the F.B.I. yet again.
In July 2016, the F.B.I. opened a highly sensitive investigation into whether any of Mr. Trump’s associates conspired with the Russians during the presidential campaign. The F.B.I. and prosecutors would later investigate Mr. Trump for obstruction after he fired James B. Comey, then the F.B.I. director, in May 2017.
A decision to open such a sensitive investigation would have required approval from senior F.B.I. officials at headquarters. Typically, opening such a high-profile case would include discussions with top Justice Department leaders, including the National Security Division.
Before proceeding with an investigation, the F.B.I. almost certainly would want an official determination from any agency involved that information was properly classified.
What role Mr. Trump played in taking the material from the White House, if any, is not publicly known. It is not likely that he would be a target of the investigation himself at the moment. In the Hillary Clinton investigation involving the emailing of classified information using a private server, the F.B.I. did not target anyone individually.
As part of any investigation, the F.B.I. would want to find out why the classified material was in Mr. Trump’s possession and who had access to it. Then agents would want to determine who packed the boxes and transported them to Florida and the circumstances surrounding that episode.
Assessing Mr. Trump’s role could be complex, in part because, as president, Mr. Trump had the ability to easily declassify whatever information he wanted.
Mr. Trump made attacking Mrs. Clinton’s mishandling of national security materials a centerpiece of his 2016 campaign. The latest revelations about Mr. Trump’s own laxity with classified information and his haphazard adherence to federal record-keeping laws have spurred Democrats to accuse him of rank hypocrisy.
The House Oversight Committee is investigating Mr. Trump’s possible violations of the Presidential Records Act and other federal statutes. The panel has been seeking information about the contents of the boxes and looking into reports that Mr. Trump “had torn up, destroyed, mutilated or attempted to tear up, destroy or mutilate” documents while in office.
The committee is also investigating reports of “White House employees or contractors finding paper in a toilet in the White House, including the White House residence.”
The Justice Department’s refusal to fully cooperate with House investigators prompted an angry letter on Thursday from Representative Carolyn B. Maloney, Democrat of New York and the chairwoman of the Oversight Committee, who accused Attorney General Merrick B. Garland’s agency of “obstructing” the panel’s work.
The National Archives informed the committee on March 28 that it was withholding information about the contents of the boxes found at Mr. Trump’s Mar-a-Lago estate and any information about any reviews conducted by other federal agencies, Ms. Maloney said in her letter.
“Based on our consultation with the Department of Justice, we are unable to provide any comment,” the archives told the committee.
“By blocking NARA from producing the documents requested by the committee, the department is obstructing the committee’s investigation,” Ms. Maloney wrote on Thursday to Mr. Garland, referring to the National Archives and Records Administration. “The committee does not wish to interfere in any manner with any potential or ongoing investigation by the Department of Justice. However, the committee has not received any explanation as to why the department is preventing NARA from providing information to the committee that relates to compliance” with the Presidential Records Act, “including unclassified information describing the contents of the 15 boxes from Mar-a-Lago.”
A Justice Department spokesman declined to comment.
Mr. Trump’s penchant for tearing up presidential records was revealed in a 2018 Politico article, but in the past few weeks, a series of disclosures has raised new questions about the Trump administration’s failure to follow federal record-keeping laws and its handling of classified information as Mr. Trump left office.
A book scheduled to be released in October by a New York Times reporter revealed how staff members in the White House residence periodically discovered wads of printed paper clogging a toilet, leading them to believe that Mr. Trump had tried to flush them.
In a recent statement, Mr. Trump said the boxed material had been turned over to the archives as part of “an ordinary and routine process” and suggested that efforts by Democrats to raise questions about his handling of the documents were a scam.
“The fake news is making it seem like me, as the president of the United States, was working in a filing room,” he said.
The clash with Mr. Garland is the latest example of congressional Democrats’ growing frustration with the Justice Department. Last week, members of the committee investigating the Jan. 6 attack on the Capitol urged the attorney general to move more quickly to charge Mr. Trump’s final chief of staff, Mark Meadows, with contempt of Congress.
One member of the panel, Representative Elaine Luria, Democrat of Virginia, told him, “Do your job so we can do ours.”
Glenn Thrush contributed reporting.