WASHINGTON -- The FBI is making a new push to determine how a woman who had an affair with retired Army Gen. David Petraeus when he was CIA director obtained classified files, part of an expanding series of investigations in a scandal that also threatens the career of the United States' top military commander in Afghanistan.
Senior law enforcement officials said a late-night seizure Monday of boxes of material from the North Carolina home of Paula Broadwell, a Petraeus biographer whose affair with him led to his resignation last week, marks a renewed focus by investigators on sensitive material found in her possession.
"The issue of national security is still on the table," one U.S. law enforcement official said. Both Mr. Petraeus and Ms. Broadwell have denied to investigators that he was the source of any classified information, officials said.
The surprise FBI move follows previous assertions by U.S. officials that the investigation had turned up no evidence of a security breach -- a factor that was cited as a reason the Justice Department did not notify the White House before last week that the CIA director had been ensnared in an e-mail inquiry.
The disclosure about the FBI's renewed focus comes as investigations of the matter expanded on other fronts.
The Defense Department announced Tuesday that its inspector general is examining hundreds of e-mails between Marine Gen. John Allen, the U.S. commander in Afghanistan, and a Florida woman also linked to the Petraeus investigation.
At the same time, key lawmakers signaled Tuesday their intent to scrutinize the Justice Department's handling of an inquiry that focused initially on a potential conflict between two private people but quickly morphed into an exhaustive examination of the e-mail of two top national security officers.
"My immediate gut is like this is the National Enquirer," Senate Intelligence Committee chairwoman Dianne Feinstein, D-Calif., said in a CNN interview. "I mean, every day there is something new." Ms. Feinstein added that she has "many questions about the nature of the FBI investigation, how it was instituted, and we'll be asking those."
White House spokesman Jay Carney said President Barack Obama maintains confidence in Gen. Allen, and that the four-star Marine Corps general will continue to lead the Afghanistan war even as he faces the inspector general's inquiry. "I can tell you that the president thinks very highly of General Allen and his service to his country, as well as the job he has done in Afghanistan," Mr. Carney said, adding that Mr. Obama "has faith in General Allen, believes he's doing and has done an excellent job."
At the same time, however, Mr. Carney said Mr. Obama put on hold Gen. Allen's nomination to serve as supreme allied commander for NATO forces in Europe, canceling Gen. Allen's appearance before the Senate Armed Services Committee this week.
The Allen investigation focuses on his extensive correspondence with Jill Kelley, a Tampa, Fla., resident who had carved out a role as an ad-hoc social ambassador to military personnel at MacDill Air Force Base.
Ms. Kelley, 37, was a close friend of Mr. Petraeus and inadvertently triggered the investigation that led to his resignation when she complained to an FBI agent earlier this year about threatening email she had received from an anonymous sender who suggested that Ms. Kelley was having an intimate relationship with Mr. Petraeus. The bureau determined that the messages were sent by Ms. Broadwell, and the inquiry exposed her affair.
The investigation also revealed that Ms. Broadwell had sent a handful of emails to Gen. Allen -- using the handle "kelleypatrol" -- including one in which she described Ms. Kelley as a "seductress" and warned him to stay away from her, according to a law enforcement official.
Close associates of Gen. Allen, who is married, said the general denied that he had an affair with Ms. Kelley, or that he had committed any wrongdoing in his communications with her. One said investigators may have misconstrued platonic references to her as a "sweetheart."
Nevertheless, the bureau turned over a mountain of documents to Pentagon officials, including an estimated 20,000 to 30,000 pages, based largely on communication between Gen. Allen and Ms. Kelley, prompting Defense Secretary Leon Panetta to order an inspector general inquiry.
The continuing FBI inquiry of Ms. Broadwell and the new Pentagon probe of Gen. Allen creates the potential for more evidence to surface, and a scandal that has already spread rapidly to expand further.
The sequence of events, and the seemingly belated disclosures that Mr. Petraeus and Gen. Allen had been ensnared in the same investigation, have placed scrutiny on the Justice Department and the FBI.
The inquiry had been under way for months before the FBI notified the director of national intelligence on election night last week that the bureau had uncovered evidence that the CIA director was having an affair.
The Allen emails surfaced as part of the same inquiry over the summer, but notification of his involvement came even later. Mr. Carney said the White House was not aware of the "situation" regarding Gen. Allen until Friday, adding that the revelations about the general and Mr. Petraeus stunned the president. "I certainly, I think wouldn't call it welcome," Mr. Carney said.
Law enforcement officials offered conflicting accounts of the significance of the FBI's seizure of materials from Ms. Broadwell's home. Officials said Ms.Broadwell provided access to the residence, which the FBI first requested on Sunday, and turned over computers, files and other material. She was not present when the search occurred over several hours Monday night.