WASHINGTON (AP) — A federal appeals court in a sealed order Wednesday directed a lawyer for Donald Trump to turn over to prosecutors documents in the investigation into the former president's retention of classified records at his Florida estate.

The ruling is a significant win for the Justice Department, which has focused for months not only on the hoarding of classified documents at Mar-a-Lago but also on why Trump and his representatives resisted demands to return them to the government. It suggests the court has sided with prosecutors who have argued behind closed doors that Trump was using his legal representation to further a crime.

The order was reflected in a brief online notice by a three-judge panel of the US Court of Appeals for the District of Columbia Circuit. The case is sealed, and none of the parties in the dispute is mentioned by name.

But the details appear to correspond with a secret fight before a lower court judge over whether Trump lawyer M Evan Corcoran could be forced to provide documents or give grand jury testimony in the Justice Department special counsel probe into whether Trump mishandled top-secret information at Mar-a-Lago.

Corcoran is regarded as relevant to the investigation in part because last year he drafted a statement to the Justice Department asserting that a “diligent search” for classified documents had been conducted at Mar-a-Lago in response to a subpoena. That claim proved untrue as FBI agents weeks later searched the home with a warrant and found roughly 100 additional documents with classified markings.

Another Trump lawyer, Christina Bobb, told investigators last fall that Corcoran had drafted the letter and asked her to sign it in her role as a designated custodian of Trump’s records.

A Justice Department investigation led by special counsel Jack Smith and his team of prosecutors is examining whether Trump or anyone in his orbit obstructed its efforts to recover all the classified documents, which included top-secret material, from his home. No charges have yet been filed. The inquiry is one of multiple legal threats Trump faces, including probes in Atlanta and Washington over his efforts to undo the election result and a grand jury investigation in New York over hush money payments. The New York case appears to be nearing completion and building toward an indictment.

Last week, Beryl Howell, the outgoing chief judge of the US District Court, directed Corcoran to answer additional questions before the grand jury. He had appeared weeks earlier before the federal grand jury investigating the Mar-a-Lago matter, but had invoked attorney-client privilege to avoid answering certain questions.

Though attorney-client privilege shields lawyers from being forced to share details of their conversations with clients before prosecutors, the Justice Department can get around that if it can convince a judge that a lawyer’s services were used in furtherance of a crime — a principle known in the law as the “crime-fraud" exception.

Howell ruled in the Justice Department's favor shortly before stepping aside as chief judge Friday, according to a person familiar with the matter, who was not authorised to discuss a sealed proceeding and spoke to The Associated Press on the condition of anonymity. That ruling was subsequently appealed, and the court records show the dispute before the federal appeals panel concerned an order that was issued last Friday by Howell.