THE FBI investigation into General David Petraeus's affair was reportedly triggered by a string of harassing emails sent by his mistress to a perceived love rival, warning her to "stay away from my guy".
Paula Broadwell, the former CIA director's biographer and reported lover, allegedly sent a number of threatening messages to Jill Kelley, 37, from Tampa, Florida, the State Department's liaison to the military's Joint Special Operations Command. She reportedly became frightened and turned to the FBI for help. As federal agents began to review the emails they quickly realised that the head of America's top intelligence agency was involved in a sexual affair with a married woman and launched an urgent investigation to see if there had been any breach of national security.
Although the emails, believed to have been sent anonymously by 40-year-old Mrs Broadwell, reportedly contained hints of classified information, the FBI concluded that there was no security threat and that they were instead looking at a bizarre case of lover's jealousy.
According to the ' New York Post', the married mother-of- two had told Ms Kelley: "I know what you did" and warned her to "back off" from the former four-star general.
It is not clear whether Ms Kelley was actually involved in a relationship with Gen Petraeus.
It remains unclear how Ms Kelley's claims of harassment were brought before the FBI rather than local police and what made federal agents believe there was a possibility 60-year-old Gen Petraeus's personal email address might have been compromised.
Mrs Broadwell did not respond to attempts to contact her at her home in Charlotte, North Carolina, nor to messages sent through her publishing agents.
US senators announced yesterday they would launch an investigation into the failure of the FBI to report Gen David Petraeus's affair with his biographer to the country's leaders until after the American presidential election.
Senator Dianne Feinstein, the Democrat chairman of the senate's intelligence committee, said that she was informed of Gen Petraeus's resignation only a few hours before it was made public on Friday, even though the FBI investigation had opened months before.
The White House said it was only informed of the affair on Wednesday, the day after the presidential election, and President Barack Obama was only briefed on Thursday, the day Gen Petraeus offered his resignation.
Mrs Feinstein, a close ally of President Barack Obama, joined with Republicans in expressing concern that the explosive news of the affair had been kept secret and that the FBI had failed to keep congress informed.
Gen Petraeus has made no public statement since his abrupt resignation on Friday, when he announced that he was stepping down because he had shown "extremely poor judgment by engaging in an extramarital affair".
Steve Boylan, a former Army officer and close confidante of the decorated commander, said that Gen Petraeus had told him over the weekend he felt he needed to "come clean with the American people".
However, that narrative seemed to contradict the account given by government officials to US media outlets, where Gen Petraeus only resigned after being confronted by FBI agents two weeks ago and was then urged to step down on Tuesday by James Clapper, the Director of National Intelligence.
Gen Petraeus met his future wife in the mid-1970s while studying at the US Military Academy at West Point, where her father was the school's superintendent.
He has often publicly praised her devotion as she stayed at home to raise their two children while he spent long postings abroad.
According to the ' Wall Street Journal', the affair began in August 2011, just as Gen Petraeus was preparing to leave the military and continued until a few months ago.
Despite the political fallout, senior figures in the CIA are reportedly satisfied that Gen Petraeus's infidelity did not lead to an intelligence leak.
Washington remained stunned over the weekend as more details emerged about the tawdry end to the career of one of America's most celebrated soldiers.
President Barack Obama said his service had "made our country safer and stronger", while Senator John McCain said he would be remembered as one of "America's greatest military heroes". (© Daily Telegraph, London)