WASHINGTON — The Justice Department has taken initial steps to investigate whether former Trump national security adviser John Bolton illegally disclosed classified information in his book, “The Room Where it Happened,” a stinging critique of the president’s decision-making on national security issues, officials familiar with the move confirmed Tuesday.

The decision to launch a criminal investigation was expected. After failing to stop the book’s publication over the summer, senior Justice Department officials said they would likely consider criminal charges.

President Trump has suggested in tweets that Bolton should be prosecuted because he “broke the law.” The latest development was first reported Tuesday by The New York Times.

“Ambassador Bolton emphatically rejects any claim that he acted improperly, let alone criminally, in connection with the publication of his book, and he will cooperate fully, as he has throughout, with any official inquiry into his conduct,” said Bolton’s lawyer, Charles Cooper of Washington, DC. Cooper said he was “aware of reports that grand jury subpoenas have been issued seeking information concerning the publication” of the book.

The government filed a lawsuit in June, seeking an emergency order to block the book’s publication. It argued that Bolton was required — because he had a top level security clearance during his government service — to wait until the White House finished reviewing the book for classified information. Instead, the suit said, he and his publisher pushed ahead and scheduled the book’s release before the process was finished.

Cooper responded to the lawsuit by saying that Bolton was required only to wait for a White House official’s confirmation that the book was free of classified information, which he received in April. The White House then launched another review, by a more senior official, which Cooper described in court as “a transparent effort to prevent Ambassador Bolton from revealing embarrassing facts about the president’s conduct in office.”

Bolton may have been required to get written permission if the book contained a type of classified material known as SCI — sensitive compartmented information. The government’s initial lawsuit did not make such a claim, but it filed a revised suit a few days later that contained the allegation.

Cooper said any such conclusion was based on a decision to classify some information at that higher level after the book was submitted for review. Bolton was required to seek review only if he believed the book contained classified information and only regarding information properly classified at that time, Cooper said.

Federal District Court Judge Royce Lamberth declined to grant the government’s motion to block publication, concluding that the book was already in the hands of distributors and retailers. But he said Bolton “gambled with the national security of the United States. He has exposed his country to harm and himself to civil (and potentially criminal) liability.”

Although the Justice Department was unable to stop the book’s publication, the lawsuit remains alive, because the government is seeking to seize Bolton’s profit from the book sales.

The book’s publisher, Simon & Schuster, declined to comment Tuesday on the government’s move to open a criminal investigation, and a Justice Department spokeswoman, Kerri Kupec, also declined comment.

PEN America, a freedom of expression advocacy group, condemned the move.

“For the Justice Department to invoke the criminal law to investigate and possibly punish a former government official for writing a book about the president and his handling of national security issues – matters of immense public concern – is a frightening affront to First Amendment values that is clearly intended to chill others from speaking out,” said Theodore Boutrous, a lawyer for the group.