American commander in Afghanistan Gen. John Allen, facing an internal investigation for "inappropriate communications" with a woman at the heart of the David Petraeus controversy, engaged in much more than "flirtatious" behavior, sources tell Fox News -- with one official even likening the email exchanges to "phone sex."
The investigation focuses on emails between Allen and Jill Kelley, a close friend of the Petraeus family. Kelley was the woman who originally notified the FBI when she received threatening emails from Petraeus' mistress Paula Broadwell -- and that investigation later uncovered the affair.
