WASHINGTON The scandal that brought down CIA Director David Petraeus started with harassing emails sent by his biographer and lover, Paula Broadwell, to another woman, and eventually led the FBI to discover the affair, U.S. officials told The Associated Press on Saturday.

Petraeus quit Friday after acknowledging an extramarital relationship.

The official said the FBI investigation began several months ago with a complaint against Broadwell, a 40-year-old graduate of the U.S. Military Academy and an Army Reserve officer. That probe led agents to her email account, which uncovered the relationship with the 60-year-old retired four-star general, who earned acclaim for his leadership of the wars in Iraq and Afghanistan.

The identity of the other woman and her connection with Broadwell were not immediately known.

Broadwell lives in Charlotte. Charlotte-Mecklenburg police spokesmen did not respond Saturday to requests for comment about any local investigation into complaints against Broadwell.

A spokeswoman for the FBI’s Charlotte office said only that Petraeus has not been a target of an FBI investigation and the agency did not investigate Broadwell for attempting to compromise the general’s computer.

There were no charges pending Saturday against Broadwell in Mecklenburg County or any other county in North Carolina, according to the N.C. Administrative Office of the Courts.

Petraeus has been married for 38 years to Holly Petraeus, the daughter of the West Point superintendent when he was a student at the New York school.

Security breach questions

Members of Congress said they want answers to questions about the affair that led to Petraeus’ resignation.

House intelligence committee chairman Mike Rogers, R-Mich., and ranking member Dutch Ruppersberger, D-Md., will meet Wednesday with FBI Deputy Director Sean Joyce, and CIA Acting Director Michael Morell to ask questions, including how the investigation came about, according to a senior congressional staffer who spoke anonymously because he was not authorized to discuss the investigation publicly.

Concerned that the emails he exchanged with Broadwell raised the possibility of a security breach, the FBI brought the matter up with Petraeus directly, according to the official, who spoke on condition of anonymity because he was not authorized to publicly discuss the investigation. The FBI approached the CIA director because his emails in the matter were in most instances sent from a personal account, not his CIA one.

Petraeus decided to quit, abruptly ending a high-profile career that might have culminated in a run for the presidency, a notion he was believed to be considering.

“Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours,” Petraeus wrote his staff.

Petraeus handed his resignation letter to President Barack Obama on Thursday, stunning many in the White House, the CIA and Congress. The news broke in the media before the House and Senate intelligence committees were briefed, officials said.

By Friday evening, multiple officials identified Broadwell, who spent the better part of a year reporting on Petraeus’ time in Afghanistan, as the other woman.

Her best-selling biography, “All In: The Education of General David Petraeus,” was written with Vernon Loeb, a Washington Post editor, and published in January.

The CIA did not comment on the identity of the woman with whom Petraeus was involved.

Broadwell had planned to celebrate her 40th birthday party in Washington this weekend, with many reporters invited. But her husband emailed guests to cancel the event late Friday.

Broadwell’s access concerns

CIA officers long had expressed concern about Broadwell’s unprecedented access to the director. She frequently visited the spy agency’s headquarters in Langley, Va., to meet Petraeus in his office, accompanied him on his punishing morning runs around the CIA grounds and often attended public functions as his guest, according to two former intelligence officials.

As a military intelligence officer in the Army Reserve, Broadwell had a high security clearance, which she mentioned at public events as one of the reasons she was well suited to write Petraeus’ story.

But her access was unsettling to members of the secretive and compartmentalized intelligence agency, where husbands and wives often work in different divisions but share nothing with each other when they come home because they don’t “need to know.”

In one incident that caught CIA staff by surprise, Broadwell posted a photograph on her Facebook page of Petraeus with actress Angelina Jolie, taken in his seventh-floor office where only the official CIA photographer is permitted to take photos. Petraeus had apparently given Broadwell the photo just hours after it was taken.

Petraeus’ staff in Afghanistan similarly had been concerned about the time Broadwell spent with their boss on her multiple reporting visits to the war zone. Following standard military procedure with senior officers, they always had another staffer present when she met with him at his headquarters. Military officers close to him insist the affair did not begin when he was in uniform.

Broadwell has deep ties and friendships throughout the Washington media and often was sought for comment on Petraeus’ viewpoints as he proved harder and harder to reach.

A lowered profile

The CIA director had lowered his media profile, stopping his practice of emailing reporters and ending once-common background interviews by the agency. That was especially the case after GOP allegations last spring that the Obama administration was leaking sensitive material to burnish its foreign policy reputation ahead of the presidential election, after a series of stories appeared about top-secret operations aimed at al-Qaida in Yemen, and Iran’s nuclear program. A White House-ordered investigation of those leaks continues.

Petreaus’ resignation comes just before a crucial scheduled appearance before congressional intelligence committees this week to testify on what the CIA knew, and what it told the White House, before, during and after the attacks that killed the U.S. ambassador and three other Americans in Libya on Sept. 11.

Congressional officials say Petraeus’ deputy, Michael Morell, will testify instead, as acting director of the CIA.

Observer staff writers April Bethea and Gary L. Wright contributed.