(CBS News) WASHINGTON - Late Friday, President Obama accepted the resignation of the director of the Central Intelligence Agency, David Petraeus, who acknowledged having an extramarital affair. CBS News also learned that for the last few months, the FBI has been investigating the communications of Petraeus. Law enforcement sources tell CBS News' Bob Orr there was concern about emails the CIA director was exchanging with a woman who is a journalist.
Additional sources tell CBS News those communications involved Paula Broadwell, 39, who published a book last year on Petraeus' time as the general in charge in Afghanistan. Broadwell is a Harvard University research associate and she spent time in Afghanistan with Petraeus. She is a West Point graduate as is Petraeus. CBS News has tried to reach Broadwell Friday but has not heard back.
Before this sudden development, it would have been hard to find anyone in Washington admired as much as Petraeus,the former four-star general led the war in Iraq and the war in Afghanistan. He is a scholar, known for his calm, steady advice to presidents.
White House officials insist they were not aware of this before Tuesday's election. They say Petraeus came here to the White House Thursday afternoon to meet with the president in person and offer his resignation. The president asked for a night to think it over and to talk with top aides. And on Friday in a phone call with Petraeus, he accepted it.
The resignation is effective immediately, just 14 months after Petreaus was sworn in as director of the CIA with his wife at his side.
In a statement to CIA employees Friday, Petraeus said: "After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair. Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours."
That statement was followed a few minutes later by this one from the president, who said he had accepted the resignation, and that: "David Petraeus has provided extraordinary service to the United States for decades. By any measure, he was one of the outstanding General officers of his generation..."
The scandal comes at a sensitive time for Petraeus and the CIA one week before Petraeus was scheduled to testify in closed-door congressional hearings about the CIA's role in fending off an attack on the U.S. consulate in Benghazi, Libya, which left the U.S. ambassador and two CIA contractors dead.
Petraeus met his wife Holly when he was a cadet at West Point. She is a top appointee at the new Consumer Protection Financial Bureau. Petraeus often describes her as "bright," "nice" and a "pit bull" -- "someone you want in your corner."
The deputy director of the CIA, Michael Morell, has been installed as acting director. White House officials described him Friday as a quote "total pro," an "all star" who advised the president on his decision to raid Osama bin Laden's compound in Pakistan.
So Morell it would seem is on the shortlist to replace Petraeus. White House officials insist they knew nothing about Petraeus' infidelity or this FBI investigation until Wednesday, the day after the presidential election.