The scandal that resulted in David Petraeus' resignation and has now ensnared the top U.S. commander in Afghanistan appeared to flare suddenly. The first the public heard about Petraeus' extramarital affair, and the FBI investigation that uncovered it, was the Friday after Election Day. But the investigation had been moving under the radar for months.
The following is a timeline, based on sources' accounts, of the still-unfolding controversy:
Spring 2006 -- Paula Broadwell meets Petraeus at Harvard University, where she is a graduate student.
October 2008 -- Petraeus is named commander of U.S. Central Command, based at MacDill Air Force Base near Tampa, Florida.
June 30, 2010 -- The Senate confirms Petraeus as the new commander in Afghanistan. Broadwell, who by this point had started a case study on Petraeus' leadership, expands her work into a biography. She makes multiple trips to Afghanistan, where she meets with Petraeus.
Sept. 6, 2011 -- Petraeus is sworn in as CIA director alongside his wife, Holly.
November 2011 -- Petraeus begins his affair with Broadwell, two months after taking command at the CIA, according to Petraeus' former spokesman Col. Steve Boylan. Boylan says Petraeus is "adamant" that the affair did not start while she was shadowing him in Afghanistan.
Jan. 24, 2012 -- Broadwell's biography, "All In: The Education of General David Petraeus," is released.
May 2012 -- Jill Kelley, a Tampa socialite and friend of the Petraeus family, starts receiving harassing emails. The FBI begins investigating soon after that.
Summer 2012 -- FBI agents determine that the email trail leads to Broadwell. They come across a private Gmail account using an alias that belongs to Petraeus. Emails between Petraeus and Broadwell lead agents to believe the two are having an affair. FBI Director Robert Mueller is notified. At some point during the investigation, the FBI interviews Petraeus and Broadwell.
July 2012 -- The affair between Petraeus and Broadwell ends, according to Boylan.
Late summer 2012-- Attorney General Eric Holder is notified.
Oct. 27, 2012 -- House Majority Leader Eric Cantor gets a tip from an FBI official about the investigation that turned up the affair -- after Rep. Dave Reichert is first notified.
Oct. 31, 2012 -- Cantor's chief of staff calls the FBI chief of staff to inform him of the call.
Nov. 6 -- On the day President Obama is elected to a second term, the Justice Department informs Director of National Intelligence James Clapper of the investigation. Clapper calls Petraeus and urges him to resign.
Nov. 7 -- Clapper informs the White House about the situation.
Nov. 8 -- Petraeus calls National Security Adviser Tom Donilon to request a meeting with Obama. Obama is briefed by staff on the situation later that day and meets with Petraeus in the afternoon. Petraeus offers his resignation.
Nov. 9 -- Obama accepts the resignation in a phone call with Petraeus. Obama calls CIA Deputy Director Mike Morell to offer him the job of acting director.
Nov. 11 -- According to the Pentagon, the FBI refers a case to the Defense Department involving Gen. John Allen, commander of U.S. and NATO forces in Afghanistan. It involves thousands of pages of emails between the general and Kelley.
Nov. 12 -- The FBI searches Broadwell's North Carolina home. Around midnight, the Pentagon reveals that Defense Secretary Leon Panetta has referred the Allen case to the Defense Department's inspector general for an investigation. Allen's nomination to be commander of U.S. European Command is put on hold.
The Associated Press contributed to this report.