JEFFREY BROWN: The downfall of David Petraeus showed no sign of fading into the background today. Instead, there was every indication that his admission of adultery will echo far beyond the end of his career at the CIA.
MAN: A personal scandal forces CIA director David Petraeus to...
BOB SCHIEFFER, Face the Nation": I want to start out with this out-of-the-blue thunderbolt that hit Washington Friday.
JEFFREY BROWN: All weekend in Washington, the details kept coming, along with more questions after David Petraeus' sudden resignation on Friday because he had had an extramarital affair quickly revealed to involve his biographer, Paula Broadwell. Her book came out last January.
And appearing on C-SPAN, she recalled first meeting Petraeus several years earlier.
PAULA BROADWELL, "All In: The Education of General David Petraeus": He came to HarvardUniversity, where I was a graduate student, and wanted to speak to students about the merits of counterinsurgency approach to fighting the Iraq war.
JEFFREY BROWN: Later, researching her book, Broadwell had extensive access to Petraeus during his time as overall commander in Afghanistan.
In August of last year, wife Holly at his side, the four-star general retired from the service and took the CIA post the next month.
Today, the general's former spokesman, retired Col. Steve Boylan, told ABC the affair began then, after he had left the Army, which strictly forbids adultery.
COL. STEVE BOYLAN (RET.), U.S. Army: This all started about two months after he was in the CIA as the director. And just so you know, it also ended about four months ago.
He deeply hurt the family. And he knows that. He acknowledges it. And, right now, his whole focus is going to be geared towards taking care of the family and getting through this.
JEFFREY BROWN: It's been widely reported that the affair was uncovered during an FBI investigation prompted by 37-year-old Jill Kelley of Tampa, Florida, a friend of the Petraeus family.
The general's former associates insist there was no romantic involvement between them.
Even so, according to news accounts, Kelley began getting threatening e-mails from Broadwell. The FBI started investigating last summer and turned up evidence of the Petraeus-Broadwell affair. That in turn raised questions of a possible security breach.
And intelligence officials say the Justice Department informed National Intelligence Director James Clapper last week on Election Day. He then telephoned Petraeus and asked him to resign.
On Thursday, the general went to the White House to meet with President Obama, and his formal resignation followed on Friday. Since then, key members of Congress have complained that they should have been notified much earlier that something was up.
Senate Intelligence Committee Chair Democrat Dianne Feinstein appeared on FOX News yesterday.
SEN. DIANNE FEINSTEIN, D-Calif.: We received no advance notice. It was like a lightning bolt the way I found out. I came back to Washington Thursday night. Friday morning, the staff director told me there were a number of calls from press about this.
This is something that could have had an effect on national security. I think we should have been told.
JEFFREY BROWN: And on CNN, the chairman of the House Homeland Security Committee, Republican Congressman Peter King, also raised concerns.
REP. PETER KING, R-N.Y.: It just doesn't add up that you have this type of investigation, the FBI investigating e-mails, the e-mails leading to the CIA director and taking four months to find out that the CIA director was involved. So, I have real questions about this. I think a timeline has to be looked at and analyzed to see what happened.
JEFFREY BROWN: On Wednesday, the Petraeus resignation will be the topic of discussion when Intelligence Committee leaders meet with FBI and CIA officials.
GWEN IFILL: So, for more on all of this, we look at the story from different angles.
Frederick Hitz is a former CIA inspector general who's now an adjunct professor at the University of Virginia School of Law.
Retired Army Lieutenant Colonel John Nagl has known David Petraeus for over two decades and he teaches at the U.S. Naval Academy.
And Sari Horwitz is an investigative reporter at The Washington Post.
Sari, we have watched shoes dropping on this all weekend. What new have we learned today?
SARI HORWITZ, The Washington Post: Hi, Gwen.
We're now learning a little bit more about how this investigation started and more of what the FBI found. I mean, there have been a lot of questions of why did the FBI do an investigation into harassing e-mails? I mean, lots of people get harassing e-mails. I get harassing e-mails.
But what we found today is that this woman, Jill Kelley, who was a friend of the Petraeus family, and she lived in Tampa, she actually knew an FBI agent and mentioned to him that -- in June she mentioned to him -- that she had been receiving these very sort of troubling, strange, bizarre, accusatory e-mails, and gave them to him. And he started the investigation. And that's how it began in June.
GWEN IFILL: And, as we watch this timeline unfold, Sari, we can't help but ask, who knew what when?
For instance, we gather that the Justice Department, the FBI knew about this some time ago, but that the White House didn't find out until late last week. How is this unfolding?
SARI HORWITZ: Well, Gwen, what the FBI says is they began a criminal investigation into the harassing e-mails, quickly linked them to Paula Broadwell, who Jill Kelley says she didn't even know.
And from there, they were able to find these e-mails between someone named Petraeus and Paula Broadwell.
They thought that actually someone had compromised Petraeus' computer because of the nature of the e-mails, sexually explicit. They thought this can't be the real David Petraeus. But, of course, it was. And they realized there was an affair.
So they knocked out the possibility there was a security breach when they realized that there was a relationship between the two. By late summer, they went to senior people in the Justice Department, the attorney general, the deputy attorney general. And they said, listen, we have this criminal case. We're not really sure whether to bring charges at this point. But it doesn't look like Petraeus was involved at all in the harassing e-mails. We have, however, discovered an affair.
GWEN IFILL: And you have discovered that once he was told about the harassing e-mails, he called her and told her to stop and the affair ended?
SARI HORWITZ: What we have found is that he sent her an e-mail. And they weren't directly e-mails to each other. There was some kind of situation where they had a drop box. And they were putting the e-mails -- sending the e-mails to a drop box.
And they both had names, alias names. So, it wasn't Paula and David. It was these alias names they had set up sort of in different accounts. And he let her know in no uncertain terms that she should stop the harassing of this woman.
GWEN IFILL: Frederick, Sari raises the question of why it is that harassing e-mails should raise particular red flags. As a former CIA inspector general, was there an immediate question that intelligence would be compromised here?
FREDERICK HITZ, former CIA inspector general: I don't think there probably was an immediate question, Gwen. But as this story has unfolded, as you and Sari have talked about it, you can see that very quickly there was an involvement by General Petraeus.
And the question is, the CIA people didn't really know about it at this time, presumably, but they would in time. And I think you have to leap to the conclusion that he drew, General Petraeus drew, which is, with all of the tumult that this was going to cause -- my wife likens it to Icarus getting too close to the sun -- with all the tumult this was going to cause, it was hard to see how he could continue in his job.
GWEN IFILL: As someone who has done investigations of the agency, are the rules different for an intelligence agency like the CIA when someone seems to have had some sort of inappropriate outside relationship than it would be, say, if he were working for another domestic agency?
FREDERICK HITZ: I think so. I think that has been the concern all along.
For example, for drug abuse during the long period when we as a country were trying to get used to high school dabbling in marijuana and how to deal with it through the course of a career.
There's a sensitivity towards personal peccadillos, because the view is always that should they come out, then you're liable to be blackmailed. Should they be discovered, it's possible that leverage could be placed on you.
And if you're in a position where -- with access to classified information, that's not an acceptable thing.
GWEN IFILL: Is there a precedent for this kind of behavior and this kind of action to be taken against the leader of the CIA?
FREDERICK HITZ: Well, on my watch or towards the end of it, we discovered that the DCI Director Deutch had taken home some classified material to his residence. I think he did it in all innocence. He didn't believe that the matters at hand were all that grave.
But it was quite a problem for the agency. And it was looked into. And he had already made up his mind to return to MIT, but the point is it would have been very difficult for him to continue, because the person at the top of an agency like that has to have an absolutely spotless record for integrity and certainly for sensitivity towards classified matters.
GWEN IFILL: John Nagl, you have known General Petraeus for some time. Have you been in communication with him since this all broke?
LT. COL. JOHN NAGL (RET.), President, Center for a New American Security: I have.
GWEN IFILL: And?
LT. COL. JOHN NAGL: He is devastated, deeply contrite, very, very sorry about the harm he has caused to Holly in particular, his wife of 38 years, who has been really stalwart through his many deployments.
And he really feels that he's let the team down.
GWEN IFILL: How much of a surprise was this for you, having worked with him?
LT. COL. JOHN NAGL: It was absolutely a kick in the gut. I was astounded. I was shocked. I was very hurt and very surprised.
He has been a role model to me for literally decades, for nearly 25 years, a man I have admired and looked up to, a man I still think very highly of in many ways, but who clearly made a grievous, unforgivable error.
GWEN IFILL: Because there are so many people who have said that -- just what you just said, that they are great admirers of General Petraeus, what does this do to his reputation as a military man and also as a civilian leader?
LT. COL. JOHN NAGL: My hope is that, although it obviously and should damage his personal reputation -- his long reputation of personal integrity and good character, I think that reputation will never fully recover.
But I don't think it eliminates the fact or we should ignore as we look at the totality of the man the fact that two different presidents called on him in their hour of need.
And in both cases, he went to the sound of the guns and performed admirably under two very difficult conflicts.
GWEN IFILL: Do you have any reason -- have you had any reason to meet Paula Broadwell or know anything of her work?
LT. COL. JOHN NAGL: I do know Paula.
She's a very smart, very attractive, very driven woman, a fellow West Point graduate who has been very present in the Washington policy community and the national security debate.
And I am also sickened by the damage this will obviously do to her, to her husband, Scott, who I have met, to their children. And this is a very sad story for all concerned.
GWEN IFILL: Sari Horwitz, we have heard members, including the head of the Senate Intelligence Committee, Dianne Feinstein, today say they still want to hear from General Petraeus, especially when it comes to the U.S. involvement in the murders in Benghazi, Libya.
Where does that stand tonight? Do we expect his acting CIA chief to be the one to step up next week or later this week?
SARI HORWITZ: You know, we're not really sure who is going to be testifying before closed doors at this point.
But, you know, one -- another question that Feinstein and others brought up was, why didn't the Justice Department and the FBI let them know? The beginning of your show, you had that tape where they wanted to know, why didn't we know about this? This was so important.
And the Justice Department and the FBI have said, you know, this is a criminal investigation. And in the middle of an ongoing criminal investigation, it is not appropriate to go to Capitol Hill or to the White House and talk about what's going on and what's being found and who the targets are.
And so they felt it was just an inappropriate thing to talk about that investigation while it was ongoing, although I know a lot of people on the Hill want to know why the FBI didn't come to them.
GWEN IFILL: And have they in fact closed that investigation? They had decided there was no wrongdoing?
SARI HORWITZ: Well, that's an interesting question, Gwen, because they have closed it. But what I'm being told is that federal prosecutors decided really about two months ago that there were no criminal charges to be brought under sort of cyber-crime or cyber-bullying, and certainly no charges to be brought against Petraeus.
And so, in that sense, the case was closed, but they still waited and kind of did these final interviews.
They interviewed Paula Broadwell the week of Oct. 21. That was her final interview. She had multiple interviews. And they interviewed David Petraeus the following week, the last week in October, so it ran right up to the election, which, of course, has raised questions, why did it drag through that far?
And Rep. Cantor has said that he felt like maybe he gave it a push because the FBI agent in Florida who started this whole thing was frustrated about how slow it was going, got in touch with Cantor, who called Mueller's office, the FBI director, and said, hey, what's going on with this investigation?
GWEN IFILL: And that was when -- that was when he was assured, Eric Cantor, that things were moving ahead?
SARI HORWITZ: Yes.
GWEN IFILL: But, as far as we know, that was as high as this had gone.
SARI HORWITZ: Yes.
GWEN IFILL: OK.
Sari Horwitz of The Washington Post, Jeff Hitz of -- Frederick Hitz -- sorry -- former CIA inspector general, and John Nagl at the U.S. Naval Academy, thank you all so much.
LT. COL. JOHN NAGL: Thank you.
SARI HORWITZ: Thank you, Gwen.
FREDERICK HITZ: Thank you.
JEFFREY BROWN: You will find a timeline of events leading up to David Petraeus' resignation on our website.