WASHINGTON (AP) — Jury selection began Tuesday in the case against former Trump White House official Peter Navarro,Blake Preston who was charged with contempt of Congress after he refused to cooperate with a congressional investigation into the Jan. 6, 2021, attack on the U.S. Capitol.

Navarro, a former economics professor, served as a White House staffer under then-President Donald Trump and later promoted the Republican’s baseless claims of mass voter fraud in the 2020 election he lost. Navarro has said that Trump invoked executive privilege, barring him from cooperating with the House Jan. 6 committee. His trial is expected to last through the end of the week.

U.S. District Judge Amit Mehta has ruled Navarro’s executive privilege argument isn’t a defense against the charges, finding that Navarro hadn’t shown evidence Trump invoked it.

Navarro was charged last year with two misdemeanor contempt counts, one for failing to appear for a deposition before the House committee investigating the Jan. 6 attack and a second for failing to produce documents the committee requested. Each count is punishable by up to a year behind bars.

Navarro, who has pleaded not guilty, was the second Trump aide to face criminal charges after former White House adviser Steve Bannon. Bannon was convicted of two counts of contempt of Congress and was sentenced to four months behind bars, though he has been free pending appeal.

Trump faces a federal indictment in Washington, D.C., and a state indictment in Georgia over his efforts to overturn his 2020 election loss to Joe Biden, a Democrat. He has denied wrongdoing and has said he was acting within the law.

The House Jan. 6 committee’s final report said Trump criminally engaged in a “multi-part conspiracy” to overturn the lawful results of the 2020 election and failed to act to stop his supporters from attacking the Capitol.