Jane Mayer at The New Yorker had the story earliest:
On Friday, James Comey, the director of the Federal Bureau of Investigation, acting independently of Attorney General Loretta Lynch, sent a letter to Congress saying that the F.B.I. had discovered e-mails that were potentially relevant to the investigation of Hillary Clinton’s private server. Coming less than two weeks before the Presidential election, Comey’s decision to make public new evidence that may raise additional legal questions about Clinton was contrary to the views of the Attorney General, according to a well-informed Administration official. Lynch expressed her preference that Comey follow the department’s longstanding practice of not commenting on ongoing investigations, and not taking any action that could influence the outcome of an election, but he said that he felt compelled to do otherwise. [...]
“You don’t do this,” one former senior Justice Department official exclaimed. “It’s aberrational. It violates decades of practice.” The reason, according to the former official, who asked not to be identified because of ongoing cases involving the department, “is because it impugns the integrity and reputation of the candidate, even though there’s no finding by a court, or in this instance even an indictment.”
Sari Horwitz at The Washington Post reports:
Senior Justice Department officials warned the FBI that Director James B. Comey’s decision to notify Congress about renewing the investigation into Hillary Clinton’s private email server was not consistent with long-standing practices of the department, according to officials familiar with the discussions.
Comey told Justice officials that he intended to inform lawmakers of newly discovered emails. These officials told him the department’s position “that we don’t comment on an ongoing investigation. And we don’t take steps that will be viewed as influencing an election,” said one Justice official who spoke on condition of anonymity to describe the high-level conversations.
“Director Comey understood our position. He heard it from Justice leadership,” said the official. “It was conveyed to the FBI, and Comey made an independent decision to alert the Hill. He is operating independently of the Justice Department. And he knows it.”
CNN adds its voice:
Attorney General Loretta Lynch and Deputy Attorney General Sally Yates objected to FBI Director James Comey's decision to notify Congress about his bureau's review of emails related to Hillary Clinton's personal server, law enforcement officials familiar with the discussion said.
Comey decided to disregard their objections and sent the letter Friday anyway, shaking the presidential race 11 days before the election and nearly four months after the FBI chief said he wouldn't recommend criminal charges over the Democratic nominee's use of the server.