WASHINGTON — The sex scandal that downed CIA chief David Petraeus has ensnared another top US general and is becoming ever more complex as it reverberates around the corridors of power in Washington.
Here is a look at the main characters and the tangled web of intrigue that links them:
GENERAL DAVID PETRAEUS
The reason this scandal is so explosive is that the man at the center of the storm is David Petraeus, the most celebrated US general of his generation.
Credited with turning around the war in Iraq in 2007, he became the commander of US forces in Afghanistan in 2010 and there was even talk of a tilt for the presidency before he became CIA chief in September 2011.
His stellar military and intelligence career came crashing to a halt on Friday when President Barack Obama accepted his resignation because of an affair with his biographer, Paula Broadwell.
The 60-year-old married father of two grown children issued an apologetic message to CIA staff:
"After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair," he said. "Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours."
The femme fatale of the drama is Paula Broadwell, a glamorous major in the Army reserve. The 40-year-old counter-terrorism expert lives in Charlotte, North Carolina with her radiologist husband and their two young sons.
Petraeus first met Broadwell when he spoke at Harvard University in 2006, handing her his card and offering his help when she told him about her research interests.
Two years later, Broadwell, who had made her dissertation topic a case study on Petraeus' leadership, was invited to join the general for a run along the Potomac River in Washington.
The keen triathlon runner later said this is when she "sealed the deal" with the general, sprinting past the renowned fitness freak to the finish.
In 2010 and 2011, Broadwell made multiple trips to Afghanistan, gaining unprecedented access to Petraeus and his command for her glowing biography: "All In: The Education of General David Petraeus."
Petraeus told friends their affair began in November 2011, two months after he became CIA chief. He says he ended it about four months ago.
The affair may never have come to light if it wasn't for Jill Kelley and Broadwell's apparent fit of jealousy.
Kelley, who is married to an oncologist in Tampa, Florida volunteered as a "social liaison" organizing events at nearby MacDill Air Force Base, home to US Central Command (CENTCOM).
She and husband Scott and their three young children live in a mansion near the base that became a party hotspot for generals and politicians.
From October 2008 until the summer of 2010, Petraeus was head of CENTCOM and the Petraeus and the Kelley families became friends.
In May this year, Jill Kelley told a local FBI agent in Tampa, who was also a friend of hers, that she had received threatening emails from an anonymous sender warning her to keep her hands off Petraeus.
Friends of both Petraeus and Kelley have denied any sexual relationship.
THE ROLE OF 'AGENT SHIRTLESS'
The unidentified FBI agent who Kelley initially went to played a key part in how events unfolded and his actions may even have forced Petraeus' resignation.
He was sidelined as the FBI cybercrime division identified Broadwell as the sender of the threatening emails. Kelley reportedly told investigators she didn't know Broadwell.
The Wall Street Journal reported that the agent was removed from the case because his supervisors were concerned he was becoming "obsessed with the matter, and prohibited him from any role in the investigation."
The agent apparently grew concerned that the FBI was sweeping the matter under the carpet and expressed those concerns at the end of October to a Washington state congressman, Republican David Reichert.
Reichert relayed the information to Republican House majority leader, Eric Cantor, who contacted FBI chief Robert Mueller on October 31.
The Washington Post has reported that Petraeus initially intended to ride out the storm.
The timeline suggests Petraeus may have changed his mind when he became aware that others in Congress knew, including Cantor, a bitter Obama opponent.
Eight days after the conversation between Cantor's office and Mueller's, and after the presidential election had wrapped up, Petraeus tendered his resignation to Obama.
The FBI operative has been dubbed "Agent Shirtless" after it emerged that he had sent shirtless photos of himself to Kelley, long before the email investigation began.
GENERAL JOHN ALLEN
The latest twist to the tale involves General John Allen, who succeeded Petraeus as US commander in Afghanistan and was deputy head of CENTCOM from July 2008 until June 2011.
Allen is being investigated for "inappropriate communication" with Kelley and the FBI is examining 20,000 to 30,000 pages of documents, many of them emails between the two.
Obama has put Allen's imminent nomination as NATO's supreme commander on hold until the matter is settled.
The Washington Post has reported that Allen also received at least one anonymous email traced back to Broadwell.
And in a further twist, the New York Daily Post revealed that Allen and Petraeus both intervened to try to help Kelley's twin sister Natalie win a bitter custody battle.