In what’s seemingly playing out as a U.S. military version of the old Abbott and Costello routine ‘Who’s on First,’ the scandal that led to revered former four-star Gen. David Petraeus’s fall from grace is enveloping an ever-expanding network of characters. Having trouble following along? Here are all the major players, and their rather complicated relationships.

Gen. David Petraeus

The retired four-star general stepped down from his post as director of the CIA on Friday after admitting to an extra-marital affair with his biographer. The 60-year-old said in a statement that he “showed extremely poor judgment” in having the affair with Paula Broadwell, a married mother of two who is 20 years his junior.

Before taking the helm of the CIA, Petraeus served as commander of NATO and U.S. forces in Afghanistan, and had served as commander of U.S. Central Command (CENTCOM) from 2008 to 2010. At one time, Petraeus had been mentioned as a potential Republican presidential candidate.

Petraeus:

  • graduated from the U.S. Military Academy at West Point in 1974.
  • married Holly Knowlton in 1974.
  • graduated top of his class from the U.S. Army Command and General Staff College in 1983.
  • earned both an MPA and a PhD from Princeton University.
  • oversaw coalition forces as commanding general of the Multi-National Force – Iraq in 2007 and 2008.
  • father to two children, a son and a daughter.

Holly Petraeus

Holly Petraeus has been married to Gen. David Petraeus for 38 years, and is mother to the couple’s two children. Sources have told U.S. media outlets that she is livid and devastated about the affair, though she has yet to speak publicly.

The former Holly Knowlton was a National Merit Scholar in high school, and graduated summa cum laude from Dickinson College. She married David Petraeus in 1974, months after his graduation from West Point.

Mrs. Petraeus serves as an assistant director at the Consumer Financial Protection Bureau, where she focuses particularly on helping military families improve and maintain their financial health. She also works on issues related to aggressive lending and foreclosure tactics by banks against military families.

Paula Broadwell

Paula Broadwell first gained international attention nearly a year ago, with the publication of her book, “All In: The Education of General David Petraeus.”

Broadwell, a research associate at Harvard and a doctoral candidate at King’s College London, turned her research into military leadership into a biography on Petraeus, and spent months with the general in Afghanistan while he was commander there. The two first met at Harvard in 2006, when Petraeus agreed to help Broadwell with her research.

The 40-year-old married mother of two also graduated from West Point and is an army reservist who has worked primarily in military intelligence, counterterrorism and counterinsurgency operations. Her affair with Petraeus, which began in the fall of 2011 and ended a few months ago, came to light after the FBI discovered she had sent emails to a woman she perceived as a rival for the retired general’s affections, Jill Kelley.

The FBI traced the emails to a Gmail account she and Petraeus used to communicate with each other. The FBI has also since found sensitive documents on her personal computer, however, Petraeus has denied that they came from him.

Jill Kelley

Jill Kelley is the Tampa, Fla., woman who went to a friend in the FBI in May with emails she perceived as threatening that were eventually traced back to Paula Broadwell.

The 37-year-old mother of three works as a volunteer social planner for U.S. Central Command in Florida. Kelley and her husband, Scott, say they have been friends with both David and Holly Petraeus for years, since he served as commander of CENTCOM beginning in 2008.

Last year, Kelley received an award for her work with CENTCOM and was named an honourary ambassador for the command.

In the first of two bizarre twists, the FBI agent who first received the emails has since been ordered by his superiors to stay away from the case after they learned he had sent shirtless photos to Kelley.

The second strange twist came early Tuesday, when it was revealed that the FBI is now probing tens of thousands of pages of emails between Kelley and another senior military officer, Marine Gen. John Allen, who took over command in Afghanistan from Petraeus last year.

Gen. John Allen

The 58-year-old U.S. Marine general was roped into the scandal after FBI officials confirmed they were investigating between 20,000 and 30,000 pages of emails between him and Jill Kelley. Officials have only said that the emails constituted “inappropriate communication,” but there has been no word about whether the emails were romantic in nature or represented a national security threat.

An unnamed senior U.S. official who is also a friend of Allen’s told the Washington Post that Allen was not having an affair with Kelley. Rather, the emails were about “routine stuff” relating to Kelley’s work with CENTCOM.

Allen, a married father of two grown daughters, assumed command of NATO troops in Afghanistan in 2011, succeeding Petraeus when he retired. Allen had been nominated to be the next Supreme Allied Commander – Europe. However, that process is now on hold pending the investigation into his email exchanges with Kelley.

Allen:

  • graduated from the U.S. Naval Academy in 1976.
  • holds a master of arts from Georgetown University, and two masters of science degrees, one from the National Defence Intelligence College and another from the National War College.
  • deployed to Iraq between 2006 and 2008, serving as the deputy commanding general of Multi-National Forces west and II MEF in Al Anbar province.
  • assumed command of NATO and U.S. Forces in Afghanistan in July 2011.