Nov. 12, 2012  -- The FBI withheld its findings about Gen. David Petraeus' affair from the White House and congressional leaders because the agency considered them the result of a criminal investigation that never reached the threshold of an intelligence probe, law enforcement sources said today.

The sources said agents followed department guidelines that generally bar sharing information about developing criminal investigations. The FBI is also aware of its history under former director J. Edgar Hoover of playing politics and digging into the lives of public figures. As one official said, the rules are designed to protect people (both private and elected officials) when negative information about them arises in the course of a criminal investigation that is not a crime.

The FBI's focus was on whether laws were broken, in this case whether federal cyber-harassment statutes were violated. The sources emphasized that Petraeus himself was never the focus of the investigation, nor did it turn up evidence he broke any law.

The focus was on his biographer, Paula Broadwell, with whom he had the affair that led to his resignation as CIA director last week.

Officials said it took time to trace the harassing emails that she allegedly sent to another woman back to her.

Because Petraeus' name was involved, criminal investigators kept an open eye for potential national security violations. They had to investigate Broadwell's background but found no evidence she was a spy.

FBI agents were at the Broadwell home in North Carolina Monday night to carry out a consensual search that had been arranged with her lawyers, law enforcement sources said. The search was to locate additional classified material on computers or documents in the home, the sources said.

Broadwell appears to be cooperating with investigators in an effort to make this go away, to show that she has nothing else to hide, the sources said.

But House Majority Leader Eric Cantor knew of Petraeus' affair with Broadwell almost two weeks before the former CIA director resigned his post.

A senior Cantor aide told ABC News that the Republican congressman from Virginia learned about the FBI investigation that brought the affair to light in a phone conversation with an FBI agent Oct. 27.

Cantor then asked his chief-of-staff to pass the information along to the head of the FBI, Robert Mueller. Cantor spoke to no one else about the investigation, the aide said.

Hurricane Sandy delayed the message to Mueller until Oct. 31. Petraeus admitted the extramarital relationship and submitted his resignation nine days later.

Meanwhile, Fury is an inadequate description for the former-CIA director's wife, Holly Petraeus' reaction after she learned that her husband had an affair with Broadwell, a former spokesman for David Petraeus told ABC News.

"Well, as you can imagine, she's not exactly pleased right now," retired U.S. Army Col. Steve Boylan said. "In a conversation with David Petraeus this weekend, he said that, 'Furious would be an understatement.' And I think anyone that's been put in that situation would probably agree. He deeply hurt the family."

As for Petraeus, the retired Army general who resigned as CIA director last week after admitting the extramarital relationship, he, "first of all, deeply regrets and knows how much pain this has caused his family," Boylan added.

"He had a huge job and he felt he was doing great work and that is all gone now."

Petraeus knows "this was poor judgment on his part. It was a colossal mistake. ... He's acknowledged that," Boylan said.

One result is that Petraeus could possibly face military prosecution for adultery if officials turn up any evidence to counter his apparent claims that the affair began after he left the military.

But Boylan says the affair between Petraeus and his biographer, Paula Broadwell, both of whom are married, began several months after his retirement from the Army in August 2011 and ended four months ago.

Broadwell, 40, had extraordinary access to the 60-year-old general during six trips she took to Afghanistan as his official biographer, a plum assignment for a novice writer.

"For him to allow the very first biography to be written about him, to be written by someone who had never written a book before, seemed very odd to me," former Petraeus aide Peter Mansoor told ABC News.

The timeline of the relationship, according to Petraeus, would mean that he was carrying on the affair for the majority of his tenure at the CIA, where he began as director Sept. 6, 2011. If he carried on the affair while serving in the Army, however, Petraeus could face charges, according to Article 134 of the Uniform Code of Military Justice, which reprimands conduct "of a nature to bring discredit upon the armed forces."

Whether the military would pursue such action, whatever evidence it accumulates, is unclear.

As the details of the investigation launched by the FBI unraveled this weekend, it became clear that the woman at the heart of the inquiry that led to Petraeus' downfall had been identified as Jill Kelley, a Florida woman who volunteers to help the military. She is a family friend of Petraeus, who Broadwell apparently felt threatened by.

Kelley and her husband are longtime supporters of the military, and six months ago she was named "Honorary Ambassador to Central Command" for her volunteer work with the military. Officials say Kelley is not romantically linked to Petraeus, but befriended the general and his wife when he was stationed in Florida. The Kelleys spent Christmases in group settings with the Petraeuses and visited them in Washington D.C., where Kelley's sister and her son live.

"We and our family have been friends with Gen. Petraeus and his family for over five years." Kelley said in a statement Sunday. "We respect his and his family's privacy and want the same for us and our three children."

Earlier this year, around the time that Petraeus and Broadwell were breaking off their affair, Kelley began receiving anonymous emails, which she found so threatening she went to authorities. The FBI traced the messages to Broadwell's computer, where they found other salacious and explicit emails between Broadwell and Petraeus that made it clear to officials that the two were carrying on an affair.

Investigators uncovered no compromising of classified information or criminal activity, sources familiar with the probe said, adding that all that was found was a lot of "human drama."

Broadwell, a married mother of two, had access to Petraeus while she was with him in Afghanistan as his official biographer. People close to the general had previously suspected Broadwell's feelings for him had crossed a professional line.

They found Broadwell, who spent a year embedded with Petraeus in Afghanistan, to be embarrassing and far too "gushy" about him. They said to one another they thought Broadwell "was in love with him," sources told ABC News.

Petraeus is said to have been the one to have broken off the extramarital affair.

His storied career, first as the public face of two wars in Iraq and Afghanistan, and later as director of the CIA, came crashing down Friday when he announced his resignation from the intelligence agency, citing the indiscretion.

"After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair. Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours," Petraeus said in a statement Friday.

Director of National Intelligence James Clapper was made aware of the Petraeus situation Tuesday evening around 5 p.m. by the FBI, according to a senior intelligence source.

After having several conversations with Petraeus that evening and the next day, Clapper advised Petraeus that the best thing to do would be for him to resign, the source said.

Clapper notified the White House the next afternoon that Petraeus was considering resigning, according to the source. Petraeus then went to the White House Thursday and told the president he thought he should resign, and Obama accepted his resignation the next day, the source said.

Despite the lengthy investigation into Broadwell by the FBI, the White House says it was not made aware of it until Wednesday, the day after the election, a revelation that surprised many.

"It just doesn't add up. That the FBI would be carrying on this type of investigation without, again, bringing it to the president or the highest levels of the White House," Rep. Peter King, R-N.Y., said.

Petraeus and his wife, Holly, who have been married for 38 years, are said to be staying in their Arlington Home and are doing "OK."

"Knowing the family, I suspect it will be hard work, but given the effort, they will get through it," Boylan, the former Petraeus spokesman, said.

Numerous questions still remain about the investigation, and some on Capitol Hill are also frustrated because Petraeus was schedule to testify to the House and Senate intelligence committees about the attack on the U.S. consulate in Benghazi, Libya, in September.

The timing of Petraeus' resignation "was what it was," an official told ABC News, adding that the time had come to tie up any loose ends in the investigation and confront the general.