CNN  — 

Justice Department officials have demanded in recent weeks to former President Donald Trump’s attorneys that he return any outstanding documents marked as classified, making clear they do not believe he has returned all materials taken when he left the White House, a person familiar with the outreach told CNN.

The Justice officials – including Jay Bratt, a top lawyer in the Department of Justice’s national security division – have communicated to Trump’s attorneys that he has an ongoing obligation to return the documents marked as classified.

The New York Times first reported on the outreach.

Whether the FBI rounded up all of the sensitive federal records in Trump’s possession during its August 8 search of his Florida residence and resort is a question that’s loomed over the situation in recent weeks.

In numerous court filings, prosecutors indicated they had concerns that classified records were possibly still missing. For instance, the Justice Department described the need to determine if other classified records still hadn’t been collected, and pointed to the empty envelopes with classified banners that were seized in the August Mar-a-Lago search.

After a federal judge blocked investigators from using the seized materials in their criminal investigation, the department said in a court filing last month that the order would “impede efforts to identify the existence of any additional classified records that are not being properly stored – which itself presents the potential for ongoing risk to national security.”

Prosecutors also told an appeals court that the judge’s order was preventing the FBI from taking investigative steps that “could lead to identification of other records still missing.”

The appeals court ultimately allowed federal criminal investigators and intelligence officials to regain access to about 100 seized documents marked as classified. But that court is still considering whether to free up access for the DOJ to use as evidence thousands more non-classified documents that were recovered in the Mar-a-Lago search.

Late last week, the Biden administration was tight-lipped on whether Trump had turned over all of the records.

“With respect to the second issue concerning whether former President Trump has surrendered all presidential records, we respectfully refer you to the Department of Justice in light of its ongoing investigation,” the National Archives told the House Oversight Committee, which had raised the question.

This story has been updated with additional details Thursday.