Retired Army Gen. David Petraeus resigned from his CIA director post last week after an FBI investigation revealed he had an extramarital affair, an investigation that also prompted questions about whether his paramour had inappropriate access to classified information.
The scandal also has sparked an investigation into whether Marine Corps Gen. John Allen, the top U.S. commander in Afghanistan, sent inappropriate messages to a different woman, leading President Obama to put Allen's nomination to become NATO's supreme allied chief on hold.
The FBI uncovered the Petraeus affair while it investigated e-mails that his paramour, Paula Broadwell, allegedly sent to a Petraeus family friend, Jill Kelley, according to a U.S. official. Kelley, meanwhile, is the woman to whom Allen allegedly sent inappropriate e-mails, according to the Defense Department.
Below is a summary of what we know about the situation.
-- Despite his resignation as CIA director last week, Petraeus will testify Friday before the House Intelligence Committee about the September 11 attack that killed four Americans at a U.S. diplomatic compound in Benghazi, Libya.
-- Petraeus has not been following the media firestorm over the extramarital affair that led to his resignation. "He wants to maintain a distance and focus on his family at this time," his aide retired Col. Peter Mansoor has said.
-- A senior law enforcement official close to the Broadwell investigation said Wednesday night that materials taken from Broadwell's home were under review, it appeared unlikely she would be prosecuted for any unauthorized release of classified information.
The Petraeus affair
-- The FBI uncovered the affair between Petraeus, 60, and his biographer, Broadwell, 40, after Broadwell allegedly sent anonymous, harassing e-mails about Kelley to Allen in May or June, according to varying accounts by officials familiar with the e-mails and the parties involved. Allen tipped Kelley off about the threats. The messages were later traced to Broadwell -- which led to the discovery of Petraeus' affair
-- It wasn't until two months later that the FBI told Kelley who had sent the e-mails, said a source close to Kelley, adding that Kelley does not know Broadwell and has never met her.
-- Kelley, 37, and her husband are friends of Petraeus and his family and friends of Allen. A Central Command spokesman said she is a volunteer with no official position at MacDill Air Force Base in Tampa, Florida where the U.S. Central Command is headquartered.
-- Investigators eventually traced the e-mails to Broadwell, a U.S. official said. They were along the lines of "stay away from my guy," but not explicitly threatening, according to the official.
-- During the investigation, other communications surfaced connecting Petraeus and Broadwell, a married mother of two living in North Carolina, an officer in the U.S. Army Reserve and a Ph.D. candidate in the Department of War Studies at King's College London.
-- Broadwell, a West Point graduate, had written a biography of Petraeus, published in January, called "All In: The Education of General David Petraeus." Having met Petraeus in 2006 when he spoke at Harvard, where she was a graduate student, she wrote the book after researching Petraeus for her Ph.D. dissertation on his leadership skills and visiting him and his team in Afghanistan, where he became top U.S. commander in 2010.
-- Petraeus and Broadwell began their affair in fall 2011, a few months after he returned to the United States, retired from the Army and took over at the CIA, according to a Petraeus friend. They ended it in summer 2012.
-- On Election Day, November 6, Petraeus told Director of National Intelligence James Clapper about the affair, according to a senior U.S. intelligence official. Clapper advised Petraeus to resign, the official said.
-- On November 9, Petraeus quit the CIA over the affair. The House and Senate intelligence committees were informed of the FBI investigation the same day.
-- Petraeus' resignation came just days before he was scheduled to testify before the Senate Intelligence Committee about the September 11 attack that killed four Americans at a U.S. diplomatic compound in Benghazi, Libya.
The Allen allegations
-- The Defense Department's inspector general is investigating allegations that Allen sent inappropriate messages to Kelley, the department said on Tuesday. The FBI told the department about the allegations on Sunday.
-- Allen has denied wrongdoing, a senior defense official said. Sources familiar with Kelley have said the relationship between the two was not sexual. Authorities are looking at the e-mails.
-- "There is no affair" between Allen and Kelley, a senior official close to Kelley said. "She is a bored rich socialite involved with every single senior commander at CENTCOM, because she worked as an honorary ambassador."
-- A U.S. official familiar with the e-mails Allen