Investigators and prosecutors determine they should investigate the case. An FBI agent asks Kelley for copies of the e-mails. A source close to Kelley says the e-mails being sent to her stop in mid-July.
Petraeus' relationship with Broadwell ends, according to friends close to Petraeus. The end of the affair was a mutual decision, says a friend.
Records of IP addresses are obtained, and Kelley is told that Broadwell (whom she does not know) is the sender of the anonymous e-mails. A U.S. official tells CNN that investigators "gained access" to Broadwell's computer. As part of the FBI's investigation, agents discover e-mails between Petraeus and Broadwell using Gmail accounts.
Petraeus tells Broadwell to stop sending harassing emails to Kelley, a U.S. official says. There is disagreement between sources exactly when this took place.
July 28
Broadwell -- by now a lieutenant colonel in the Army Reserve -- appears on a panel at the Aspen Institute.
"I was embedded with Gen. Petraeus in Afghanistan, and it was a little confusing to some of the folks there because I am also a military reservist with a top-secret FBI clearance and then some," Broadwell told the audience.
Late summer
The FBI informs the Justice Department about the investigation. By this time, the FBI has long concluded there was no national security breach, but continues investigating whether Petraeus had any role in the harassing e-mails sent to Kelley. It is not clear when FBI Director Robert Mueller and Attorney General Eric Holder are informed.
September
Petraeus and Allen both write letters on behalf on Jill Kelley's sister Natalie Khawam, who is in the midst of a custody battle.
September/October
FBI investigators interview Broadwell. There's confusion over the date -- variously reported as some time in September, or as late as the week of October 21. A law enforcement source tells CNN's Fran Townsend that Broadwell gave authorities her computer at this time.
October 26
Broadwell talks to students at the University of Denver, and says: "The CIA annex (in Benghazi, Libya, during the attack on September 11, 2012) had actually had taken a couple of Libyan militia members prisoner and they think that the attack on the consulate was an effort to try to get these prisoners back. So that's still being vetted."
(On November 13 Sen. Susan Collins says she is surprised that Broadwell "had access to some classified information. We don't know whether that is true or not.")
October 27
Petraeus and Broadwell both attend the Office of Strategic Services Dinner in Washington. They do not sit together.
Late October
The FBI agent in Tampa -- Humphries -- who had been approached by Kelley reaches out to office of Rep. Dave Reichert, R-Washington, to express concern about lack of progress in the investigation. Reichert contacts House Majority Leader Eric Cantor, according to Cantor spokesman Doug Heye. Heye says Cantor had a conversation with the agent, described as a whistle-blower, about the affair and subsequently Cantor's chief of staff notified FBI Director Mueller.
"I received information from an individual that I had not met before and did not know," Cantor said later. "The information that was sent to me sounded as if there was a potential for a national security vulnerability."
FBI investigators interview Petraeus. There's disagreement over the date. The Washington Post reports it's October 29.
November 2
The FBI wraps up its case after interviewing Paula Broadwell a second time.
November 5
Broadwell offers CNN "a short essay on (Petraeus') leadership principles in light of" his 60th birthday. "Sorry I have been incognito-focused on the phd!" she adds.
November 6 (Election Day)
Petraeus' boss, Director of National Intelligence James Clapper, is informed of the probe in a phone call from the FBI at around 5 p.m. He speaks with Petraeus and advises him to resign.
November 7
Clapper notifies staff that Petraeus -- who turns 60 this day -- is considering resigning and why.
November 8
Newly re-elected President Barack Obama is informed. Petraeus visits the White House to hand in his resignation.
White House spokesman Jay Carney says later: "The president was certainly surprised when he was informed about the situation regarding General Petraeus on Thursday."
November 9
The president accepts Petraeus' resignation during a phone call. Petraeus steps down as director of the CIA, days before he was scheduled to testify before the Senate Intelligence Committee about the September 11 attack in Benghazi.
According to a congressional aide familiar with the matter, the House and Senate intelligence committees weren't informed that there was an FBI investigation before November 9.
Obama is also made aware of the investigation into Allen when the Department of Justice notifies White House counsel that there may be an issue associated with Allen's nomination, according to National Security Council spokesman Tommy Vietor.
November 11
Lawmakers complain in televised interviews that the FBI didn't alert them sooner to the investigation.
Sen. Dianne Feinstein, D-California, who chairs the Senate intelligence committee, says on Fox: "We received no advance notice; it was like a lightning bolt."
