Jill Kelley leaves her home in Tampa, Florida. Kelley is identified as the woman who allegedly received harassing emails from General David Petraeus' paramour, Paula Broadwell.

Washington -

The military scandal gripping America took an extraordinary twist on Tuesday night when a second general was linked to one of the two women who precipitated the fall of CIA director General David Petraeus.

Petraeus, 60, hailed by some as the finest officer of his generation, was forced to step down after the exposure of a scandal involving X-rated emails, compromised state secrets and an affair forged in the ruins of Afghanistan.

The spy boss’s mistress was revealed as Paula Broadwell, a glamorous defence academic and ex-army officer, who had written a fawning biography of Petraeus after she was “embedded” with him in Afghanistan.

Though they conducted their affair via private email accounts and with sufficient discretion to hoodwink even the suspicious minds of his CIA subordinates, it came to light thanks to old-fashioned female jealousy.

Broadwell became convinced that she was, in fact, involved in a love triangle - and not one that involved Mrs Petraeus.

The “other woman”, a 37-year-old Florida socialite and mother of three named Jill Kelley, went to the FBI after receiving threatening emails from Broadwell. But, almost incredibly, the investigation she set in train not only led to the demise of Petraeus, but has ensnared another senior figure.

On Tuesday, the Pentagon announced that General John Allen, 58 - who was about to be appointed Nato’s Supreme Allied Commander in Europe - is being investigated for “inappropriate communication” with Mrs Kelley.

While investigating Kelley’s case, the FBI discovered what it says amounts to between 20 000 and 30 000 pages of emails between her and General Allen between 2010 and 2012. On Tuesday, some of those emails were described by a senior defence official as “flirtatious”.

Allen, 58, succeeded Petraeus as the head of US forces in Afghanistan, but his new European post is now on hold. Like Petraeus, he got to know Mrs Kelley when he was stationed at Central Command near her home in Tampa, Florida, where she organises social events for senior military families.

Not only has the widening scandal been disastrous for the Petraeus, Broadwell and Kelley families, but it has also caused major ructions in Washington as the first nightmare of the new Obama presidency.

Angry congressmen are demanding to know why FBI and Justice Department investigators failed to alert them months ago to a case that clearly had repercussions for national security.

Congressman Peter King, chairman of the House Homeland Security Committee, on Tuesday called the latest revelations a “Greek tragedy”, comparing events to a “Hollywood movie or a trashy novel”.

It was Obama who appointed Petraeus to run the CIA (as he did Allen to the Nato job), and some Republicans suspect there might even have been a cover-up to put off until after last week’s election a scandal that might embarrass the President.

The Justice Department - of which the FBI is part - has countered that it is supposed to refrain from sharing information about its criminal investigations with senior politicians. As soon as they decided there would be no criminal charges, officials say they informed Washington.

The news of the affair between Petraeus and Broadwell wasn’t a complete bombshell for those who worked closely with the general. The extraordinary access he provided to the 40-year-old - first in Afghanistan, where he commanded US forces after the Iraq war, and later at CIA headquarters in Virginia - did raise eyebrows with some subordinates.

But many thought a sexual affair was impossible. For Petraeus’s private life was as famously exemplary as his public one.

Openly contemptuous of fellow officers who were unfaithful to their wives, Petraeus’s 38-year marriage to wife Holly - a tireless campaigner for service families’ rights - was held up as a blueprint for how military families could survive the intense strains of extended separation.

But now it has been undone by a lover who might be described as Action Woman to his Action Man. The green-eyed, lithely built and highly intelligent Broadwell liked to boast she and her general were brought together by the fact they both did army officer training at West Point military academy and were obsessed with physical fitness.

They met six years ago at Harvard, where he was giving a speech about counter-insurgency and she was working on a master’s degree in defence studies.

She went up to him afterwards, expressed her admiration and they exchanged business cards. Broadwell later asked for his help on a dissertation on his leadership style that she was writing as part of a PhD under the supervision of the department of war studies at King’s College, London.

When he took over the war in Afghanistan in 2010, she decided to turn her dissertation into a book, and asked if she could come and watch him in action.

They weren’t lovers then, he has told friends, but they certainly became as close as one can imagine any mentor and protegee could ever be. Despite her being a novice writer, Petraeus - or “Peaches” as we now know his mistress called him - agreed she should write his official biography.

He allowed her to fly out to see him in Kabul six times in little more than a year, and she was given a room in his headquarters. Most early mornings saw the couple going off on five-mile runs together, with her interviewing him as they jogged.

“I thought I’d test him, but he was going to test me - it ended up being a test for both of us since we both ran pretty quickly,” she bragged of her first run to TV host Jon Stewart, in an interview earlier in 2012 in which she showed off her toned arms in a sleeveless top.

Just as Petraeus had two children - one of whom has also served in Afghanistan - so does Broadwell. Despite striking others as just as fiercely ambitious as Petraeus, she has described herself as a “soccer mom”, bringing up two young boys in a smart part of Charlotte, North Carolina, while juggling her academic and writing career.

Her CV includes appearing in the occasional advert for a machine-gun manufacturer. Her husband, Scott, is a radiologist and a fellow fitness nut, and the couple met while doing military service in Germany.

Petraeus has told friends that he and Broadwell didn’t start an affair until several months after he retired from the army in August 2011 to take over the CIA, and that it ended four months ago, at his instigation.

But were they sharing a room in July 2011 when she accompanied him on a government-funded trip to Paris shortly after he was appointed to run the CIA?

Like his subordinates in Afghanistan, CIA staff were irked by the access that Broadwell was given to their boss, turning up regularly at the Agency’s high security HQ in Langley, Virginia, and often appearing as his guest at public events.

What they were actually getting up to is revealed in some of the emails recovered by the FBI when it started investigating Broadwell several months ago. One missive even reportedly referred to “sex under a desk”.

Thanks to a drip-drip of disclosures from unnamed officials, we now know that the FBI was approached by the “other” woman, Mrs Kelley, after she received half a dozen emails in May, apparently from an angry woman using a variety of email addresses.

Mrs Kelley, 37, a wealthy surgeon’s wife, does unpaid work as a social ambassador for the local military HQ - bragging about her role with a number plate on her Mercedes that reads “Honorary Consul”.

She and her husband became close friends of Petraeus and his wife after the general was stationed near Tampa in 2008.

She first approached an FBI agent of her acquaintance, who referred the emails to a cyber crimes unit. However, he was taken off the case after superiors reportedly discovered he was obsessed with Mrs Kelley and was sending shirtless pictures of himself to her (yet another odd detail in this utterly extraordinary case).

The agent then contacted a Republican congressman, saying he feared his bosses were trying to sweep the matter under the carpet.

For its part, the FBI insists that when it was approached by Mrs Kelley, it had no idea General Petraeus was involved. The emails - sent to an address Mrs Kelley shared with her husband - were vaguely menacing, but puzzling, using such language as “back off” and “I know what you did”.

Another accused her of “parad[ing] around the base . . . you need to take it down a notch”. (Given the vampish yellow dress, stilettos and lurid pink bag Kelley sported this week, you can perhaps see what the author of the emails was getting at.)

In yet another, the anonymous writer claimed to have seen Mrs Kelley touching “him” provocatively under the table. But the emails never mentioned Petraeus by name.

Some FBI agents considered the missives too trivial to warrant following up, but - encouraged by Mrs Kelley’s FBI chum - investigators spent weeks tracing where the emails had been sent from, and eventually matched them to hotels where Paula Broadwell had been staying.

Gaining a warrant to monitor her emails, they discovered Broadwell and Petraeus - using a pseudonym - had set up private Google Mail accounts to send steamy messages to each other. (Terrorists use the technique, by which the sender can leave messages in a “draft” folder so the recipient can log in and read them without anything being emailed.)

By late summer, the FBI had workedout the general was involved and - alerting the US Justice Department and Attorney General Eric Holder - they interviewed Broadwell in September.

She admitted the affair and agreed to hand over her computer. On its hard drive, investigators found copies of undisclosed classified documents - a discovery that inevitably rang even louder alarm bells. (Federal agents returned to her home on Monday night and removed boxes of documents and two computers.)

Confronted by the FBI with its evidence the week before the presidential election, Petraeus also admitted to the affair, but insisted he hadn’t sent the secret material to his mistress.

Officials are reportedly convinced he is telling the truth, but still don’t know how the documents were found on Broadwell’s computer.

Finally deciding there was insufficient evidence to bring charges against either of the lovers, officials briefed Petraeus’s boss James Clapper - director of national intelligence - on election day last week. They told him they were concerned the CIA boss had left himself exposed to blackmail.

Clapper told Petraeus he had to step down - something that insiders say the former general had not contemplated - and he went to the White House the following day and handed in his resignation letter.

The extent of Jill Kelley’s relationship with Petraeus remains unclear: she has said only that she and her family have been ‘friends’ with the Petraeuses for years.

Former aides of the general who monitored his emails when he went to Afghanistan say the pair kept in touch almost every day, but the messages were not romantic.

A friend of Mrs Kelley who did not want to give her name said “Jill would flirt with all the senior military guys” invited to parties at her home.

“She is a very sexy lady and she knows it . . . she’s touchy-feely,” said the friend. “Her hands would be on their arms. She would be attentive. It’s not hard to see why she had some guys under her spell.”

As we now know, Petraeus wasn’t the only general with whom she was in regular email contact.

While last night General John Allen remained in his job leading the American forces in Afghanistan - and was given a vote of support by President Obama - he could be prosecuted under military law for ‘bringing discredit on the armed forces’ if it emerges he had an affair with Mrs Kelley.

An unnamed senior official close to him yesterday insisted they exchanged only a couple of hundred emails over a few years and that ‘most of them were routine stuff’. He stressed that there has never been an affair, and that if Allen sometimes called her “sweetheart” it was only a term of platonic endearment.

While Allen’s future remains uncertain, David Petraeus must now face the humiliation of his calamitous actions.

Friends say he is “devastated” at the pain he has caused his family, as well he might be. Still living at the marital home, he told a friend his wife is so angry that “furious would be an understatement”.

Though it seems unlikely, in theory he could also be prosecuted under military law for “bringing discredit on the armed forces” if it emerges the affair started when he was still a serving general.

America, meanwhile, has lost one of its few warrior pin-ups at a time when its military ventures around the globe are hardly meeting with stunning success.

Army colleagues nicknamed the imperious Petraeus “King David” - and it was not meant as a compliment. Now, some have noted with little regret that like the Biblical king who was punished by God for seducing his general’s wife, Petraeus has been brought down by his own Bathsheba. - Daily Mail