FBI probe of Petraeus began with "suspicious emails"
U.S. General David Petraeus gestures during the Senate Intelligence Committee hearing on his nomination to be director of the Central Intelligence Agency on Capitol Hill in Washington in this June 23, 2011, file photo. REUTERS/Yuri Gripas/Files
Director of the Central Intelligence Agency General David Petraeus attends the Allen & Co Media Conference in Sun Valley, Idaho July 12, 2012. REUTERS/Jim Urquhart
U.S. Army Gen. David H. Petraeus, commanding general of the NATO International Security Assistance Force (ISAF) and U.S. Forces Afghanistan (USFOR-A), delivers remarks before he administers the oath of re-affirmation and re-enlistment to U.S. service members at Kandahar Airfield in Kandahar in this Photo taken July 4, 2011. REUTERS/Haraz N. Ghanbari/U.S. Navy/Handout
Central Intelligence Agency Director David Petraeus (R) and his wife Holly prepare to ring the opening bell at the New York Stock Exchange, September 18, 2012. REUTERS/Brendan McDermid/Files
CIA Director David Petraeus speaks to members of a Senate (Select) Intelligence hearing on "World Wide Threats" on Capitol Hill in Washington in this January 31, 2012 file photo. CIA Director David Petraeus has submitted a letter of resignation to President Barack Obama, Director of National Intelligence James Clapper said on November 9, 2012. REUTERS/Kevin Lamarque/Files