WASHINGTON — The Justice Department declined to prosecute the former F.B.I. director James B. Comey after determining that two memos he wrote about his interactions with President Trump contained classified information and examining whether he mishandled the documents, according to people familiar with the matter.
The F.B.I. upgraded the memos to confidential — the lowest level in the government’s system of classifying information — shortly after the president fired Mr. Comey in May 2017, the people said. Mr. Comey had kept several memos at his home and shared one with a friend when he thought they contained only routine information, but the determination that some memos included classified material prompted the investigation into whether he mishandled them.
Prosecutors quickly determined the case did not warrant charges, the people said. It is not clear which memos spurred the inquiry, but the upgrade to confidential dealt with foreign relations, a person familiar with the classification review said.
The Justice Department’s inspector general, Michael E. Horowitz, has been investigating Mr. Comey’s handling of the memos but has said little about the inquiry. A report on his findings is expected to be delivered by the fall.
John S. Lavinsky, a spokesman for the inspector general’s office, declined to confirm or deny the existence of the investigation.
Mr. Comey’s memos, first revealed in the days after his dismissal two years ago, jolted Washington and infuriated the president with their accounts of Mr. Trump’s demands of loyalty from law enforcement. Mr. Comey later told lawmakers that he had sought to make them public in part to prompt the appointment of a special counsel.
Mr. Comey wrote several memos after he met with Mr. Trump in the first days and weeks of his presidency, saying later that he worried that the president “might lie” about their discussions. Mr. Trump and his allies accused Mr. Comey of illegally leaking the memos as they tried to undermine his standing as a key witness in the investigation by the special counsel, Robert S. Mueller III.
The F.B.I. collected four memos from Mr. Comey’s house in Virginia in June 2017, and he told agents he had written two others but could not find them. The F.B.I. eventually recovered seven memos in total, which were later turned over to Mr. Mueller. Congress made the memos public in April 2018 and Mr. Comey wrote about them in a book published last year.
Mr. Comey showed copies of a memo to a friend, Daniel C. Richman, a professor at Columbia Law School, Mr. Richman has confirmed. “I asked a friend of mine to share the content of the memo with a reporter,” Mr. Comey testified to Congress in June 2017. “I thought that might prompt the appointment of a special counsel.”
Mr. Trump’s request to Mr. Comey that the F.B.I. end an investigation into Michael T. Flynn, the president’s first national security adviser, was revealed in a New York Times article that cited one of the memos. The Justice Department announced the appointment of a special counsel the next day.
“Confidential” is the lowest of the three classification levels established by an executive order that regulates the handling of government information deemed sensitive. The highest level, “top secret,” is applied to information whose unauthorized disclosure could be expected to cause “exceptionally grave damage” to national security. Leaks of “secret” information would cause “serious damage” and of “confidential” information, mere “damage.”
The Justice Department typically does not prosecute the mishandling of confidential information.
The Hill newspaper first reported that prosecutors had decided not to pursue Mr. Comey.
Congress released the bulk of the memos last year. News outlets, including The Times, have sued for their full text. But the F.B.I. has argued in the lawsuit that parts of the memos must remain private because of national security concerns.
In June, a Federal District Court judge in the District of Columbia upheld only some of the F.B.I.’s redactions, ruling that other information that officials had blacked out must be revealed.
The judge, James E. Boasberg, said that the F.B.I. had to peel back redactions in most of the information related to Mr. Flynn, deeming the F.B.I.’s arguments for secrecy inadequate.
“The bureau has provided no line of reasoning linking the disclosure of these redactions to any harm to the United States’ relations with a foreign country or leader and a consequent harm to national security,” Judge Boasberg wrote.
He also ordered the F.B.I. to be more transparent with some information in the memos concerning conversations that Mr. Comey and Mr. Trump had about leaders of other countries.
Mr. Comey’s memos were also closely guarded pieces of evidence in the special counsel’s investigation into whether the president obstructed justice, which ended this year. When news organizations first sued the Justice Department for access to them, prosecutors for Mr. Mueller told Judge Boasberg that making them public risked compromising testimony from those under investigation, who could have tailored their responses to line up with Mr. Comey’s accounts.