FBI role in Petraeus investigation questioned

(CBS News) David Petraeus is telling friends and colleagues that there was only one affair, and he is devastated by the affair that led to his resignation Friday as director of the Central Intelligence Agency. There have been a lot of questions about how the FBI came to uncover the affair through an investigation of e-mails.

While late Monday FBI officials visited the home of Paula Broadwell, Petraeus' mistress, for what they described as a "consensual search" to clean up lingering issues, the four-month investigation by the FBI was wrapped up just days before the election. In the end, agents did not find any evidence of an intelligence breach. Instead, they uncovered the tawdry personal affair that brought down CIA chief David Petraeus.

It started as a low-level cyber investigation in Tampa, Florida. Jill Kelley, a socialite who's done fundraising for the U.S. military, told a friend in the FBI that she'd received a series of anonymous harassing emails. Agents quickly traced those emails to a former military intelligence officer, Paula Broadwell, the author of the biography, "All In: The Education of General David Petraeus."

The FBI investigation began in June with about a half-dozen emails from Broadwell to Kelley. While the emails did not openly name Petraeus, some of them contained information about his travel schedule -- details the public wouldn't usually have access to.

This raised concerns at the FBI that someone may have breached Petraeus' computer or email files. In the end investigators determined Broadwell got that sensitive travel information from Petraeus himself, and without his knowledge. She incorporated the information into the emails sent to Kelley. It took investigators quite a while to determine this was not the result of a breach.

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A further investigation turned up numerous emails, some of them sexually explicit, between Broadwell and Petraeus. At first blush, investigators wondered if someone had breached Petraeus' private email. Investigators had actually stumbled across an extra-marital affair.

Petraeus and Broadwell exchanged hundreds, if not a few thousand, emails and messages over a number of years. Some of the information they traded was not actually emailed, but written and left in draft files which they each could read by accessing a common private email account. Draft emails, because there is no electronic transfer record, are not easily found by cyber investigators.

Officials suspect Broadwell sent the email messages to Kelley believing her to be a romantic rival. Sources say when Petraeus became aware of those messages, he asked Broadwell to stop sending them.

Petraeus became friends with Kelley when he was in charge of the U.S. Central Command in Tampa. But, the retired four-star general has told friends he was never romantically involved with Kelley.

Petraeus has however admitted his affair with Broadwell to the FBI and told friends it began after he took charge of the CIA in September 2011.

The affair was ongoing when Broadwell -- a married mother of two -- was on a media tour promoting her Petraeus book.

During her book tour, Broadwell said of Petraeus: "Yes, he is a very high energy person. And I think he does gain energy from feeling that he is consequential and making a difference."

Petraeus, one of America's most decorated soldiers, has called his infidelity "unacceptable," unfair to his wife Holly, whom he publicly praised at his military retirement.

"Needless to say I will never be able to adequately express my love and dedication for all that she has done. But I can at least say here this morning, thanks, Holl, I love you," Petraeus said.

The FBI investigation now is winding down. No one faces charges. Members of congressional intelligence committees are angry they were not put in the loop during the Petraeus investigation. But, the FBI says with no national security issues involved, such notification was not required.

Officials have confirmed a report by the Wall Street Journal that the Tampa FBI agent who first brought the case to the Bureau's attention has been reassigned and his status is being reviewed by the FBI.

There is not yet an official investigation. The agent is a personal friend of Jill Kelley's. When she received Broadwell's harassing emails, this agent pushed the cyber squad in Tampa to investigate. Over time he became disgruntled when higher-ups in the FBI essentially cut him out of the information flow of the investigation. He then took his concerns of a possible cover-up to a congressman friend who forwarded the information to Rep. Eric Cantor.

The Wall Street Journal notes this agent once sent a shirtless picture of himself to Jill Kelley. This apparently is true, but happened a long time ago, well before this investigation.

CBS News has been in contact with a friend of Petraeus, who says he's been in touch with Petraeus on a regular basis since Friday. He says Petraeus is deeply disappointed in his own behavior. He says his wife Holly is furious about the whole thing.

Petraeus is telling close associates: "I had the best job with the best organization and I threw it all away."

Then he added: "I messed up."