An aide to former President Donald Trump who has said he was present as Trump declassified broad categories of materials has appeared before a federal grand jury after being given immunity for his testimony, according to a person familiar with the matter.

Kash Patel appeared Thursday after the Justice Departmen t agreed to grant him immunity from prosecution for his testimony and after a federal judge in Washington entered a sealed order to that effect.

He had invoked his Fifth Amendment right against self-incrimination during an earlier appearance before the grand jury, but the Justice Department — in an apparent acknowledgment of his importance as a witness — later offered him the form of immunity that protects him from having his testimony used against him.

The Justice Department is conducting a criminal investigation into the discovery of top-secret records seized in an FBI search of Trump’s Florida property, Mar-a-Lago, on Aug. 8. The FBI removed more than 100 documents with classification markings during that search. T hat’s in addition to 15 boxes of records recovered in January by the National Archives and Records Administration, as well as more than three dozen classified documents turned over to investigators in June.

Patel is of interest to investigators because of his claims, including in a May interview with Breitbart News, that he was present as Trump declassified material even though no changes had been made to classification markings on the documents. In that interview, Patel said, Trump “declassified whole sets of materials in anticipation of leaving government that he thought the American public should have the right to read themselves.”

Trump’s lawyers have stopped short of asserting that he had declassified material that was later found at Mar-a-Lago, though they have noted that a president has broad declassification authority.

Patel’s testimony, first reported by The Washington Post, was confirmed by a person familiar with the matter who spoke to The Associated Press on condition of anonymity to discuss an ongoing investigation. A Justice Department spokesman declined to comment.

Separately, FBI agents have interviewed a former deputy White House counsel in the Trump administration in May and June about Trump’s handling of classified information as president, a person familiar with the matter told AP on Friday.

That lawyer, John Eisenberg, told investigators that he did not help pack the boxes that were taken to Mar-a-Lago and had no knowledge of what documents they contained. He also said he had no recollection, as Patel has asserted, of Trump broadly or unilaterally declassifying sets of information, the person said.

Eisenberg told agents that he believed a president had broad declassification authority, but that the scope of the power also depended on the context and specific nature of the information involved.

He also recounted for investigators an episode in which Trump wanted to tweet sensitive information related to a rocket on a launch pad. He said that he had reached out to a stakeholder agency to see if that would be a problem, and that certain markings were then removed.

(AP)