“The FBI probe into the sex scandal that prompted CIA Director David Petraeus to resign has expanded to ensnare Gen. John R. Allen, the commander of U.S. and NATO troops in Afghanistan, the Pentagon announced early Tuesday,” the Washington Post reports.

“According to a senior U.S. defense official, the FBI has uncovered between 20,000 and 30,000 documents — most of them e-mails — of “potentially inappropriate” communications between Allen and Jill Kelley, a 37-year-old Tampa woman, whose close relationship with Petraeus ultimately led to his downfall. Allen, a Marine, succeeded Petraeus as the top allied commander in Afghanistan in July 2011.”