The woman at the center of the David Petraeus cheating scandal warned another woman to ‘back off’ and ‘stay away’ from the retired general in threatening emails uncovered by the FBI.

Petraeus quit his post as director of the CIA on Friday while offering an apology over the affair, allegedly with his biographer, Paula Broadwell.

His apology came as reports show that the affair blew up in Petraeus’ face after Broadwell allegedly sent the e-mails to another woman whom she accused of getting too close to him.

The recipient of those emails, fearing for her safety, contacted the FBI – which found that Broadwell had sent them.

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

The official added: ‘[Broadwell] clearly thought something was going on’ and thought she was in a ‘lovers triangle.’

Little is known about the recipient of those emails, including her identity, but the paper reported that she was not Petraeus’ wife.

Broadwell, who is married with two young sons, has not responded to multiple emails and phone messages.

She had planned to celebrate her 40th birthday in Washington this weekend, with many reporters invited. Her husband Scott emailed guests to cancel the party.

It is also claimed that Broadwell used Petraeus’ own Gmail account to send the emails, and when the FBI began to investigate an obvious national security issue instead uncovered explicit messages between the two sent from the decorated war hero’s own account – indicating an affair.

Three senior law enforcement officials with knowledge of the case told the Washington Postthat when Petraeus’ name was raised in connection with the threatening emails, the FBI thought that security had been breached. CIA officers long had expressed concern about Broadwell’s unprecedented access to the director.

She frequently visited the spy agency’s headquarters in Langley, Virginia, to meet Petraeus in his office, accompanied him on morning runs around the CIA grounds and often attended public functions as his guest, according to two ex-intelligence officials.

Beginning their investigation into how the Director of the CIA’s personal email had been hacked, the FBI agents instead uncovered evidence that he and 40-year-old Broadwell were involved in an extramarital affair.

FBI investigators first interviewed Petraeus about what they had found two weeks ago and informed him that no criminal charges would be brought and no-one is thought to have discussed the possibility of his resignation.

But, according to theWashington Post, after an investigation Justice Department officials were unclear what to do next, because no crime had occurred nor breach of security.

They contacted James Clapper, the Director of National Intelligence and told him they had compromising material about Petraeus.

Clapper in turn spoke to Petraeus and advised him to resign.

‘Director Clapper learned of the situation from the FBI on Tuesday evening around 5pm,’ the intelligence official said to theWashington Post

‘In subsequent conversations with Director Petraeus, Director Clapper advised Director Petraeus to resign.’

Director Clapper also added that he did not see the need for an internal investigation by the CIA, citing it as ‘a very personal matter, not a matter of intelligence.’

On Wednesday evening, Clapper went to the White House and on Thursday morning President Obama was informed.

Later on Thursday, Petraeus arrived to see the President and offered his resignation, which was accepted on Friday.

- Daily Mail