A federal judge has at least partially granted a request from U.S. prosecutors to force an attorney for Donald Trump to testify before a grand jury about the former president’s possession of classified documents after leaving office, according to two people briefed on the decision.

The lawyer, Evan Corcoran, had refused to answer investigators’ questions about his interactions with Trump, invoking attorney-client privilege – a principle of U.S. legal practice that says lawyers must keep confidential what they are told by their clients.

U.S. prosecutors argued that there are exceptions to the privilege, including when there is evidence that a client used the attorney’s legal services in furtherance of a crime. In secret court filings and a hearing held behind closed doors earlier this month, people familiar with the matter said, prosecutors sought to show Chief U.S. District Judge Beryl A. Howell of Washington that there were grounds for a “crime-fraud exception.”

Howell agreed, said the two people briefed on the ruling, who spoke on the condition of anonymity to discuss a sensitive matter. Her decision was first reported by CNN.

Trump’s team is expected to ask incoming Chief U.S. District Judge James E. Boasberg, who succeeds the term-limited Howell as of midnight Saturday, to stay her order while they appeal, the people familiar with the matter said.

The people did not provide details of Howell’s decision, and the scope of what questions Corcoran must answer was not clear. Trump’s team will not see the ruling until next week, the people said, after the Justice Department has a chance to propose redacting portions that deal with investigative details that prosecutors want to keep secret.

Howell’s decision appears to mark a victory for prosecutors, as they investigate whether Trump or anyone around him committed a crime and should face charges after an FBI search of the former president’s home in August turned up more than 100 documents with classified markings. The government had tried for more than a year to recover any documents in Trump’s possession after he left the White House, and had issued a subpoena months before the search demanding any material with classified markings.

Trump spokesman Steven Cheung said the prosecutors’ efforts to solicit testimony from Corcoran was a sign that their investigation was in trouble.

“Whenever prosecutors target the attorneys, that’s usually a good indication their underlying case is very weak,” he said in a statement. “Every American has the right to consult with counsel and have candid discussions – this promotes adherence to the law. We will fight the Department of Justice on this front and all others that jeopardize fundamental American rights and values.”

Corcoran handled the Trump team’s initial responses to government requests to retrieve documents that were still in the possession of the former president. He gave assurances to the Justice Department that he led a diligent review of the documents in Trump’s possession in response to the May 2022 subpoena, and had identified and handed over all classified records. Documents recovered after that, in the FBI search, included highly sensitive material about Iran and China, The Washington Post has reported.

The Justice Department is investigating whether Trump or anyone around him mishandled classified documents at Mar-a-Lago, or obstructed the investigation or efforts to retrieve the material. Prosecutors have shown interest, according to people with knowledge of the case, in efforts from Trump and advisers to avoid giving materials back to the government and whether they lied to any federal government officials.

Corcoran appeared before the grand jury hearing evidence in the case in January, according to two people familiar with the investigation who spoke on the condition of anonymity to discuss a sensitive matter. He was asked whether he spoke with Trump about missing documents or the search he conducted in response to the subpoena, a person familiar with his testimony said. But he repeatedly declined to provide information, asserting Trump’s right to have conversations with his attorney remain private, the person said.

Special counsel Jack Smith – appointed to lead the investigation in November, after Trump announced he was again running for president – has increased scrutiny of Trump’s legal team in recent weeks, turning some of his many current or former attorneys into witnesses or potential investigative targets.

The special counsel’s office declined to comment on Howell’s ruling on Friday, and a lawyer for Corcoran did not respond to requests for comment.

Smith’s office is also leading a separate investigation into whether efforts to interfere with the transition of power from Trump to President Biden after the 2020 election violated criminal laws. In that investigation, he has subpoenaed former Trump administration officials including former vice president Mike Pence, whose lawyers have said he will resist the subpoena by asserting a different type of privilege.

In addition to the special counsel probes, Trump is under investigation in Georgia for his alleged efforts to overturn the results of the 2020 presidential election in that state, and in Manhattan for his role in making hush-money payments to a former adult-film star during the 2016 campaign. The film star, Stormy Daniels, claimed she’d had an affair with Trump years earlier. He has denied the affair and denied wrongdoing in the documents and elections-related matters as well.