(WASHINGTON) -- Paula Broadwell, the author who allegedly had an affair with former CIA Director David Petraeus, is suspected of storing significant amounts of military documents -- including classified material -- at her home, potentially in violation of federal law.
A source familiar with the case told ABC News that Broadwell admitted to the FBI that she took the documents from secure government buildings. The government demanded that they all be given back, and when federal agents descended on her North Carolina home Monday night, it was a pre-arranged meeting.
Prosecutors are now determining whether to charge Broadwell with a crime. The FBI and military will be pouring over the material Wednesday morning.
The 40-year-old author, who wrote the biography on Gen. Petraeus, All In: The Education of General David Petraeus, is cooperating. The case is complicated by the fact that as an intelligence officer in the U.S. Military Reserve, she had security clearance to review the documents.
The FBI found classified material on a computer voluntarily handed over by Broadwell earlier in the investigation. Prosecutors will now have to determine how important the classified material is before making a final decision. Authorities could decide to seek disciplinary action against her rather than pursue charges.
Senior FBI officials are expected to brief the House and Senate Intelligence Committees Wednesday on their handling of the Petraeus investigation. The officials are expected to lay out how the case was developed and argue that there were no politics involved.
The case is so critical that FBI Director Robert Mueller may attend the briefing to defend the bureau, ABC News has learned. Members of Congress have been angry that they were not informed about the case before the story was reported by the media, but FBI officials maintain that their guidelines forbid them from discussing ongoing criminal cases.
This summer, Florida socialite and "honorary ambassador" to the military Jill Kelley received anonymous emails accusing her of flaunting a friendly relationship with military brass in Tampa, Fla. Kelley then called the FBI, which traced those emails back to Broadwell's computer. Investigators are said to have then found emails in Broadwell's inbox that pointed to an intimate affair with Petraeus, who on Friday admitted to the affair and announced his resignation as CIA director.
The FBI has now uncovered "potentially inappropriate" emails between Gen. John Allen, the commander of American forces in Afghanistan, and Kelley, according to a senior U.S. defense official who is traveling with Defense Secretary Leon Panetta. The department is reviewing between 20,000 and 30,000 documents connected to this matter, the official said. The email exchanges between Kelley and Allen took place from 2010 to 2012.
The U.S. official said the emails were "innocuous" and mostly about upcoming dinner parties and seeing him on TV.
Allen denies he was involved in an affair, a Pentagon official said. An intermediary for Allen told ABC News that Allen and his wife are friends with Kelley and her husband and most of the emails were sent from Kelley to Allen's wife.
A U.S. official said Allen may have triggered the investigation when he got an anonymous email a few months ago that was traced to Broadwell. The email had a "Kelley Patrol" return address or subject line and painted Kelley as a seductress, which Allen found alarming and mentioned to Kelley in a subsequent email, the official said.
Panetta cautioned that "no one should leap to any conclusions" about allegations against Allen over the investigation. The defense secretary said he supports Allen, who has been in command in Kabul since July 2011. He took over that summer for Petraeus, who retired from the Army to take over as the head of the CIA.
"He certainly has my continued confidence to lead our forces and to continue the fight," Panetta said at a news conference in Perth, Australia, Wednesday.
Secretary of State Hillary Clinton, who appeared with Panetta, declined to comment on the Allen case, but insured the scandal has not harmed the war effort.
"There has been a lot of conversation, as you might expect, but no concern whatsoever being expressed to us because the mission has been set forth and it's being carried out," Clinton said.
Allen had been nominated as the next commander of U.S. European Command and the commander of NATO forces in Europe, and despite President Obama's backing, the nomination has been put on hold. The change of command at NATO is currently slated to not take place until March at the earliest.
Allen was supposed to appear before a Senate confirmation hearing on Thursday alongside his designated replacement, Marine Gen. Joseph Dunford. Panetta said that while the matter is being investigated by the Defense Department inspector general, Allen will remain in his post as commander of the International Security Assistance Force, based in Kabul.
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