Marc Short, who was chief of staff to then-Vice President Mike Pence during the assault on the U.S. Capitol, confirmed he has testified to a grand jury investigating the matter.

Short, attending the Young America’s Foundation annual National Conservative Student Conference in Washington where Pence was speaking, confirmed he complied with a subpoena but declined to offer further details.

Short would be one of the highest-ranking people to be called before the federal grand jury.

The New York Times and Wall Street Journal reported Monday that Greg Jacob, another top Pence aide, was also subpoenaed in the inquiry and testified before the grand jury.

Attorney General Merrick Garland told reporters Wednesday that the Jan. 6 probe “is the most wide-ranging investigation and the most important investigation that the Justice Department has ever entered into,” he said.

Short testified before a House committee investigating the insurrection that he warned the head of the vice president’s Secret Service detail the day before the Jan. 6 congressional session that he could be in danger.

“My concern was for the vice president’s security,” Short said in a video excerpt from a deposition he gave the committee.

Short, in that recorded deposition, said then-President Donald Trump’s chief of staff Mark Meadows didn’t think the plan for Pence to block election certification was legal.

Meadows told Short that he didn’t agree with the legal strategy, Short testified. White House Counsel Pat Cipollone described it as “nutty,” Trump adviser Jason Miller said. And Trump senior adviser Eric Herschmann called it “completely crazy.”

Jacob testified that then-Vice President Al Gore would have elected himself president if he could have thrown away votes during the 2001 electoral count.

“Don’t you think Al Gore might have liked to have known in 2000 that he had the authority to declare himself president of the United States?” Jacob said he said to Trump lawyer John Eastman.