‎A federal appeals court ruled Wednesday that a lawyer representing former President Donald J. Trump’s handling of classified materials must answer questions from a grand jury and provide prosecutors with documents related to their legal work.‎

‎The U.S. Court of Appeals decision for the District of Columbia was a victory for the special counsel overseeing the investigation and came after President Trump tried to prevent attorney M. Avon Corcoran from handing over dozens of documents to investigators.‎

‎The behind-the-scenes fighting has shed new light on prosecutors’ efforts to gather evidence about whether Mr. Trump committed a crime in violation of government efforts to recover classified material taken after leaving the White House.‎

‎The lawsuit, conducted behind closed doors or under a cell, focuses on whether prosecutors can force Mr Corcoran to provide information about the continued presence of classified material at President Trump’s residence in Florida and private club Mar Lagoo, when the government called for its return last spring.‎

‎The focus of the prosecution in particular is on the document that Mr. Corcoran drafted last spring that said there was a “diligent search” in Mar Lago and that there was no further classified material left — a claim that would be proven false. Prosecutors are trying to find out what Mr Trump knows about the statement.‎

‎The case involves striking a balance between the privileges of the lawyer and the client, which usually prevents lawyers from giving private communications with their clients to the government, and a special provision of the law known as the criminal fraud exemption. This immunity allows prosecutors to breach the privileges of lawyers and clients when they have reason to believe that legal advice or legal services have been used to advance an offence, usually by the client.‎

‎The feud began last month when special counsel Jack Smith’s office tried to break the attorney client’s privilege claims made by Mr. Corcoran and Mr. Trump in the documents inquiry. ‎‎During his initial appearance before a grand jury investigating the case‎‎, Mr Corcoran stressed this privilege to limit the scope of the questions he must answer as well as the number of legal records.‎

‎But in an effort to get as much information as possible from Mr. Corcoran, Mr. Smith’s office used ‎‎the immunity from criminal fraud‎‎ in a filing to Judge Beryl A. Howell sitting in the Federal District Court in Washington. Prosecutors working for Mr. Smith wanted Judge Howell’s attorney to set aside the client’s privileges and force Mr. Corcoran to give him what he wanted.‎

‎On Friday, Judge Hoyle ‎‎issued a ruling‎‎ saying the government had met the threshold for fraud in crimes, and prosecutors initially claimed that President Trump had violated the law in terms of documents.‎

‎Judge Howell said that “the government has prima facie shown that the former president committed criminal violations” does not mean that prosecutors have enough evidence to indict President Trump. Instead, it was enough to set aside the privileges of lawyer and client and justify Mr. Corcoran providing information about his conversations with Mr. Trump.‎

‎As part of his decision, he ordered Mr. Corcoran to return most of the legal documents he had tried to withhold and send it back to the grand jury to give more complete answers to prosecutors’ questions. His order also outlines half a dozen areas of investigation that the Justice Department wants Mr. Corcoran to answer questions about.‎

‎But on Tuesday night, as Mr. Corcoran began preparing to comply with the judge’s order, Mr. Trump’s lawyers requested the Appeals Court to stay the decision as they tried to overturn parts or all of his decision. The court initially temporarily stayed the decision and set an unusually aggressive schedule for the case, asking Mr Trump to submit his nomination papers by midnight and the government to file a response by 6 a.m. on Wednesday.‎

‎The appeals court’s decision on Mr Corcoran has opened up a long-standing threat to the government’s case. Although the court accepted Judge Hoyle’s decision that forced Mr. Corcoran to provide the prosecutor with information to stand for the time being, it also allowed the main appeal of the decision to proceed.‎

‎The move opened up the possibility that if the appeals court or the Supreme Court eventually ruled that the government’s arguments about fraud impunity in crimes were inaccurate, prosecutors would be prevented from using the information mr Corcoran provided as evidence to obtain in a grand jury indictment or any case. were.‎

‎Depending on the stage of any case, it can prove fatally harmful. The prosecution must therefore examine the risk in deciding whether to make any use of the evidence before fully resolving the merits of the dispute.‎

‎Although the case has now passed through two different courts and has been documented several times, it is not yet clear whether the government believes the crime was committed or who else else may have committed it other than or other than Mr. Trump.‎

‎Yet one of the topics the Justice Department has been examining since last year is whether Mr. Trump or his aides obstructed justice by failing to comply with repeated calls from the White House after he left office to return a wealth of official material brought with him, including hundreds of documents with secret markings.‎

‎In May, before Mr. Smith took over the investigation as special counsel, federal prosecutors issued an injunction about any classified documents mr. Trump had in his possession — when he voluntarily handed over the initial shipment of records to the National Archives containing about 200 classified documents.‎

‎In response, Mr. Corcoran met with federal investigators in June and gave them another set of documents, more than 30 of which had rating marks.‎

‎In August, FBI agents ‎‎searched Mar Lagoo with a‎‎ warrant. During the search, three secret documents were found on the desk inside President Trump’s office, including more than 100 documents in 13 boxes or containers with classification marks in the residence, some of which were at a very limited level.‎

‎Nearly three weeks after Mr. Corcoran’s meeting with investigators in June, federal prosecutors issued another sub-order for camera surveillance footage near a storage room in Margo. According to a person familiar with the matter, the topics that Mr. Smith’s office wants mr. Corcoran to testify about include a phone call he spoke to Mr. Trump when the subpoena for video footage was released.‎

‎Prosecutors are also interested in two men caught in surveillance footage while moving boxes from a storage room in Margogue, according to two people familiar with the matter. One of them was former White House aide Walton Nota, who went to work for Mr. Trump in Florida. The other was a labourer working in Mar Lagoo.‎