Kerry may be choice for secretary of defense Security shuffle follows Petraeus’s departure ← Related Article Visit The Boston Globe Share on Twitter Share on Facebook Comment on this Scroll to top of page Musadeq Sadeq/AP Photo US General John Allen, the top commander of US forces in Afghanistan, allegedly exchanged flirtatious e-mails with Jill Kelley. Chris O'Meara/AP Photo Jill Kelley, a friend of David Petraeus, allegedly received threatening e-mails from Petraeus girlfriend Paula Broadwell. ISAF/Getty Images Former CIA director Davis Petraeus met Paula Broadwell in 2006, when she was a student at the Harvard Kennedy School of Government. T. Ortega Gaines/The Charlotte Observer/AP Photo Broadwell co-wrote the Petraeus biography "All In," and the two began their affair shortly after Petraeus was named CIA director. Win McNamee/Getty Images Petraeus’ resignation left President Obama, shown with Petraeus in June 2010, searching for a new CIA director. Paul Richards/Reuters Secretary of Defense Leon Panetta (right), with Allen (left) and Petraeus (center) in 2011, has indicated he will not stay for Obama’s second term. AP Photo/Mary Altaffer Senator John Kerry of Massachusetts, previously considered a contender for secretary of state, may become the next defense secretary. Saul Loeb/AFP/Getty Images John Brennan, Obama’s chief counterterrorism adviser, is said to be a strong candidate for Petraeus’ CIA position, officials said. Dennis C. Enser/Buffalo News/AP Photo Michael Morell, associate deputy director of the CIA, could become the director if Brennan declines the job, officials said.