Discuss as:

Lawmakers question timing of Petraeus resignation

Officials say the FBI investigation into David Petraeus was triggered  by a complaint from a family friend into emails sent by his biographer Paula Broadwell. NBC's Andrea Mitchell reports.

Updated at 12:17 a.m. ET: As more details about General David Petreaus’ alleged relationship with his biographer emerge, lawmakers on both sides of the aisle have expressed frustration, asking when the affair was discovered and who in Washington was told about it.

“We received no advance notice; it was like a lightning bolt,” Sen. Dianne Feinstein, D-Calif., said on “Fox News Sunday.” Feinstein chairs the Intelligence Committee. “We should have been told. There is a way to do it.”

Petraeus, who was appointed 14 months ago to head the Central Intelligence Agency, announced his resignation on Friday, citing an extramarital affair. Multiple government officials tell NBC News that he had a relationship with Paula Broadwell, 40, who wrote about the general’s education in her bestselling book, “All In.”

Steven Boylan, who worked for the former CIA director, told NBC News that he had spoken with Petraeus over the weekend and that he said his relationship with Broadwell lasted nine or 10 months and ended four months ago.

Of Petraeus’ wife, Holly, Boylan said that to suggest that she’s furious is an “understatement.”

On CNN, Peter King, R-N.Y., chair of the Homeland Security committee said: “It seems this has been going on for several months, but now it appears that they’re saying the FBI didn’t realize until Election Day that General Petraeus was involved. It just doesn’t add up.”

Officials tell NBC News that the affair was revealed because Broadwell sent anonymous, threatening emails to Jill Kelley, 37, described as a close friend of the Petraeus family. Kelley, who lives in the Tampa, Fla. area, was a volunteer social liaison to MacDill Air Force Base in Tampa.

Investigating who sent the emails to Kelley, the FBI discovered the connection between Petraeus and Broadwell, officials say.

Petraeus was interviewed in late October, officials told NBC News. But it wasn’t until Thursday that he met with President Barack Obama, who accepted his resignation on Friday.

The woman who complained of being harassed by Paula Broadwell, General David Petraeus' biographer, has been identified as Jill Kelley, 37, a senior official tells NBC News. NBC's Kristen Welker reports.

Lawmakers question the timing not just because the news was delivered so soon after the elections, but because Petraeus was scheduled to testify Thursday about the attacks on the Benghazi, Libya consulate that resulted in the deaths of Ambassador Chris Stevens and three other Americans.

Those lawmakers argue that Petraeus is the key to receiving answers about the attacks.

A senior law enforcement official tells NBC News that the investigation was “overseen carefully.”

"The investigation had to take a certain path, step by step. Things needed to be explored, and there were sensitivities to observe,” the official said.

House Majority Leader Eric Cantor, R-Va., however, said that he was earlier told about the situation by an FBI employee.

"I was contacted by an FBI employee concerned that sensitive, classified information may have been compromised and made certain (FBI Director Robert) Mueller was aware of these serious allegations and the potential risk to our national security,” Cantor said in a statement.

“A senior law enforcement official says a call to a congressional staffer came from an agent who was initially involved in the investigation but who was later removed from the case because he knew an associate of one of the people being investigated.  The agent knew someone on the Hill and called that person, a Republican staffer, according to the official. But that phone call had no effect on either the course of the investigation, the involvement of FBI Director Robert Mueller -- who was following it closely long before Cantor called him -- or the decision to notify Director of National Intelligence James Clapper, the official says.”

Meanwhile, Boylan told NBC News in an interview on Saturday that he was “very surprised and shocked” at the news.

"He's not perfect, he's made a mistake," Boylan said. “I don’t know if ‘let down’ would be right word … my first reaction was disbelief and then wondering if there wasn't somebody out there was spinning something to try to do some kind of harm 'cause that's happened in the past.”

Petraeus: Battlefield 'hero' and savvy Washington insider

Boylan said he interacted with Broadwell during the early stages of research for her book. He said he didn’t recall Petraeus ever commenting to him about Broadwell.

“Based on my initial contact with her on email, telephone, she sounded driven, she seemed smart on the topic,” he said. “Anyone probably doing their dissertation knows the rigors of research and is going to have to be dedicated in that direction.”

NBC News has been unable to reach Petraeus, Broadwell or Kelley for comment.

"He's not perfect, he's made a mistake," said Steven Boylan, who worked for Gen. David Petraeus before the CIA director resigned following the discovery of his extramarital affair. NBC's Kristen Welker reports.

Kristen Welker is NBC News’ White House correspondent. Pete Williams is NBC News' justice correspondent. This story includes reporting from NBC's Andrea Mitchell and The Associated Press.


More content from NBCNews.com:

Follow US news from NBCNews.com on Twitter and Facebook