(CBS News) FBI officials have already said their investigation into the scandal that brought down David Petraeus hasn't turned up any threat or damage to national security.
But, reports CBS News correspondent Bob Orr, since his affair with Paula Broadwell occurred while Petraeus was the director of the Central Intelligence Agency, the CIA's inspector general has begun an internal investigation.
Sources say the CIA is looking into the general conduct of Petraeus over the 14 months he headed the agency before resigning last week after acknowledging the affair.
Petreaus was to testify behind closed doors to two congressional panels Fridayabout the Sept. 11 attack on the U.S. Consulate in Benghazi, Liba that left four Americans dead, including Ambassador Christopher Stevens.
CIA spokesperson Preston Golson tells The Associated Press the probe is "exploratory" and "doesn't presuppose any particular outcome."
But, says Orr, the inspector general wants to make sure Petraeus didn't misuse any agency assets in the process of carrying on his affair with Broadwell.
Petraeus told CNN Thursday he never gave any classified information to Broadwell.
Petraeus also told CNN his resignation had nothing to do with his testimony to Congress about the Benghazi attack, and that he wanted to give the testimony.
A search of Broadwell's computer turned up intimate emails with Petraeus and also revealed Broadwell may have mishandled some classified information that she'd collected for a biography she wrote of him.
The FBI found a substantial number of classified documents on Broadwell's computer, and she has told agents she took classified documents out of secure government buildings.
The bureau also found classified documents in a search of Broadwell's house Monday in Charlotte, N.C. Broadwell had agreed to the search and had told agents in advance that there would be more of them there.
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