Fresh reports piled pressure on Monday on FBI and CIA officials to explain the circumstances and timing of an investigation that ended the storied career of spy chief David Petraeus just three days after President Barack Obama's re-election.

Petraeus, an American hero credited with turning the tide of the Iraq war, resigned as head of the Central Intelligence Agency on Friday after admitting an extramarital affair, sparking concerns of a security breach and sending shockwaves around Washington.

A leading Republican on Sunday questioned why, if there were serious concerns about comprised intelligence, it had taken several months for the FBI to finally notify the Obama administration.

"It just doesn't add up," Peter King, the top Republican on the House Homeland Security Committee, told CNN. "I have real questions about this. I think a timeline has to be looked at and analyzed to see what happened."

The questions were expected to multiply following a New York Times report on Monday that high-level officials at the Federal Bureau of Investigation and the Justice Department had known about Petraeus's affair since late summer, but did not notify anybody outside of the agencies until last week.

The law requires that the Senate and House intelligence committees be kept "fully and currently informed" of what the CIA and FBI are doing.

And Senate Intelligence Committee Chairman Dianne Feinstein made it clear Sunday she was not pleased.

Appearing on the "Fox News Sunday" television show, she said she wanted to know why the FBI didn't notify the intelligence committees sooner.

"We should have been told," Feinstein remarked.

The US government is closed on Monday as part of the Veterans Day holiday. But on Tuesday, when the government reopens, senior FBI and CIA officials were scheduled to meet with leading members of Congress to bring them up to date about details of the probe, media reports said.

It has emerged that the woman he was having an affair with is Paula Broadwell, a 40-year-old former Army major granted unprecedented access to the general as she co-authored a best-selling biography: "All In: The Education of General David Petraeus."

Newspaper reports on Sunday revealed that the affair came to light after the FBI was called in as part of a criminal investigation launched when a second woman complained that she had received vicious emails from Broadwell.

The threatening and harassing emails from Broadwell, a married mother of two, indicated that she thought the other woman was a potential rival for the 60-year-old general's affections, officials told the US media.

A government official told The New York Post that the emails contained such language as: "I know what you did," "back off" and "stay away from my guy."

-- Second woman --

US media identified the other woman as 37-year-old Jill Kelley, a "social liaison" to a Florida air force base who apparently had a longstanding friendship with Petraeus but no official status in the military.

The recipient of the emails was so frightened, according to the Washington Post, that several months ago she went to the FBI for protection and to help track down the sender.

The FBI soon uncovered Broadwell's sexually explicit correspondence with Petraeus, leading to initial fears of a national security breach if someone had broken into the CIA chief's private email account.

Broadwell lives in North Carolina with her radiologist husband Scott and their two young sons. She planned to celebrate her 40th birthday with a big party in Washington this weekend, but the event was reportedly canceled.

Kelley said in a statement that her family and the Petraeuses had been friends for five years. Her husband, also named Scott, is an oncologist.

"We respect his and his family's privacy and want the same for us and our three children," she said in the statement sent to ABC News.

A close friend of Petraeus told ABC News it was "very clear there was nothing going on other than friendship" between the general and Kelley.

-- Replacement headache --

Obama's director of national intelligence James Clapper was only informed of the situation on Tuesday evening, providing a dramatic behind-the-scenes backdrop to the president's re-election night.

Clapper discussed things with Petraeus on Wednesday and advised him "the right thing to do would be to resign," an intelligence official told the Times. Obama was not told until Thursday morning, the White House said.

Republicans have pointed to the fact that Petraeus was days away from testifying about the September 11 attack on the US consulate in Benghazi, Libya as evidence of some kind of conspiracy.

Petraeus had been due to testify Thursday about the Benghazi attacks that killed Ambassador Chris Stevens and three other Americans. CIA deputy director Michael Morell, now acting director, will testify in his place.

The stunning departure of Petraeus has left Obama with an added headache as he begins his second term.

The president will likely have to replace not only departing Secretary of State Hillary Clinton, but also Defense Secretary Leon Panetta and Treasury Secretary Tim Geithner.

One name being floated as a possible Petraeus replacement is John Brennan, the White House counter-terrorism adviser and a CIA veteran who has played an instrumental role in Obama's drone war against Al-Qaeda militants.