An FBI spokesperson declined to comment on Comey's role in the decision-making surrounding the Oct. 7 statement.
According to the former official, Comey agreed with the conclusion the intelligence community came to: "A foreign power was trying to undermine the election. He believed it to be true, but was against putting it out before the election." Comey's position, this official said, was "if it is said, it shouldn't come from the FBI, which as you'll recall it did not."
Comey took a different approach toward releasing information about the discovery of emails on a laptop that was used by former congressman Anthony Weiner and his estranged wife Huma Abedin, the official said.
"By doing a press conference, and personally testifying and giving his opinion about the conduct, he made this about James Comey and his credibility," the official said. "You can see why he did it, from his perspective, once he had had that press conference."
The official said FBI investigators can get a "preliminary read" of the newly discovered emails within a couple of days and come to an initial conclusion about whether there is classified material in the files. "The questions is whether they will decide to share that read or not," the official said. "Normally in the FBI we would not, but we're not in normal land anymore."
Comey's decision to announce the new investigative steps has come under severe criticism from Democrats, including Hillary Clinton who addressed the issue at a rally Monday.
"I'm sure a lot of you may be asking what this new email story is about and why in the world the FBI would decide to jump into an election with no evidence of any wrongdoing with just days to go. That's a good question," Clinton said. "I am sure they will reach the same conclusion they did when they looked at my emails for the last year. There is no case here."
The Donald Trump campaign, meanwhile, has praised Comey for continuing to investigate Clinton. "The right thing to do is whatever the FBI thinks," said Trump campaign manager Kellyanne Conway on CNBC Monday morning. "It's not for us to say speed it up because of the election or slow it down because of the election."