John R. Bolton, the national security hawk and former adviser to President Trump who became one of his most outspoken critics, was indicted by a federal grand jury in Maryland on Thursday on charges of mishandling classified information.

The indictment against Mr. Bolton was 18 counts and accused him of using personal email and a messaging app to share more than 1,000 pages of “diary” notes about his day-to-day activities as Mr. Trump’s national security adviser in 2018 and 2019. The notes, which were sent to two family members who did not have security clearances, included national defense information, such as details classified as top secret, according to the indictment.

President Trump and his former aide parted bitterly toward the end of his first term, and the president greeted the news with grim satisfaction. “He’s a bad guy,” Mr. Trump said in response to a question from a reporter at the White House about Mr. Bolton. “That’s the way it goes.”

While Mr. Bolton is part of a string of perceived enemies of the president to become prosecutorial targets, the federal investigation into him gained momentum during the Biden administration, when U.S. intelligence agencies gathered what former officials have described as troubling evidence.

The prosecution appeared to follow normal department channels, without firings or forced transfers. Kelly O. Hayes, the U.S.