Petraeus resignation: Just sex scandal or serious security concern? (CBS News) The sudden downfall of CIA Director David Petraeus seems to have been rooted in simple jealously, but the scandal is raising new questions about the security of top-secret U.S. government information and the CIA's role in the response to the deadly attack on the U.S. Consulate in Benghazi, Libya. The FBI uncovered evidence of an affair between Petraeus and his biographer Paula Broadwell after she allegedly sent harassing emails to another woman, Jill Kelly, who Broadwell seems to have thought was too close to Petraeus. The FBI investigation found only a personal drama and no security issues connected to the affair, and no charges are expected, reports CBS News correspondent Bob Orr. Petraeus was scheduled to testify before Congress on Thursday about the deadly Sept. 11, 2012 attack on the U.S. Cosulate. Now his Deputy Mike Morell is to fill that role, but lawmakers made it clear over the weekend that they will still likely want to hear from Petraeus on the matter. Republican Senator Lindsey Graham told Face the Nation that Petraeus was still the CIA's man who knows the most about Benghazi. Click on the player above to hear Graham's remarks "I don't see how in the world you can find out what happened in Benghazi before, during and after the attack if General Petraeus doesn't testify," Graham told Face the Nation. Petraeus is said to be focused now on his family, but the chairman of the House Homeland Security Committee has said the timing of the resignation suggests a coverup, and several members of the House and Senate have told CBS News correspondent Sharyl Attkisson they're confident Gen. Petraeus will be called to testify about Benghazi in the not-too-distant future. Timeline: How the Benghazi attack, and probe, unfolded Diane Feinstein, the Democrat who leads the Senate Intelligence Committee, said she sees Petraeus' resignation the Friday before his scheduled appearance as coincidental, but doesn't rule out a future appearance. CBS News has learned that Gen. Petraeus visited Libya near the end of October -- and called several members of Congress the week before he resigned, saying that surveillance video of the Benghazi attack supported an element of spontaneity -- as the Obama administration first claimed. At least one Republican reportedly expressed strong disapproval to Petraeus over standing by that analysis. Click on the player above for a full report from inside the scorched Benghazi compound Meanwhile, a video has surfaced that shows Petraeus' mistress and biographer Broadwell giving information about the attack that some say may indicate she was privy to sensitive information. Speaking at the University of Denver in late October, Broadwell responds to a question about Petraeus role in the Benghazi scandal by saying, "I don't know if a lot of you heard this, but the CIA annex had actually, um, had taken a couple of Libyan militia members prisoner and they think that the attack on the consulate was an effort to get these prisoners back. So that's still being vetted. The CIA has said virtually nothing about its operation in Benghazi -- based at a consulate annex about a mile away from the main building -- or how much Ambassador Chris Stevens knew about that operation and the level of danger it may have put his mission in. U.S. officials struck back at allegations at the beginning of November that they had failed to respond quickly or efficiently to the deadly attack on the consulate, detailing for the first time a broad CIA rescue effort. At left: CIA says Benghazi response took 25 minutes Senior U.S. intelligence officials said CIA security officers went to the aid of State Department staff less than 25 minutes after they got the first call for help from the consulate. The agency has vehemently denied the claims made by Broadwell in her Colorado address, insisting that prisoners were not held at the CIA annex in Benghazi. It is unclear whether Broadwell was simply confusing information reported by Fox News earlier in the day, or whether she was relaying what she believed to be inside information on the Benghazi attack from her high-level government sources - who included Gen. Petraeus. The New York Times reports that in the course of its investigation into the emails, the FBI found classified documents on Broadwell's computer, according to a government source. CBS News senior correspondent John Miller says the FBI seems to have been satisfied that Petraeus was not the source of the documents, but if the report is accurate, it raises further questions about the level of access she enjoyed as a private citizen to some of the nations most senior officers, and sensitive information. (At left: Miller and Gen. Richard Myers (Ret.) discuss implications of the Petraeus scandal) Attkisson reports that Petraeus hasn't been the only high ranking official to leave his post since the Benghazi assault. Gen. Carter Ham is in the process of stepping down as commander of U.S. Africa Command (AFRICOM). He was in charge of U.S. military operations in Libya and the surrounding region on that night. And Gen. Joseph Dunford is stepping down as the Marine Corps' 2nd in Command. The Pentagon has called both moves routine successions. The Navy has replaced Charles Gaouette, the Rear Admiral who commanded the USS Stennis aircraft carrier Strike Group in the Middle East due to recent allegations of "inappropriate leadership judgement," which were not otherwise described. Paula Broadwell, meanwhile, has made no public comment on the affair since the news broke, or on her comments in Colorado regarding Benghazi.