TAMPA, Fla. (AP) — If you were to diagram the increasingly tangled sex scandal involving former CIA Director David Petraeus, nearly all lines would lead back to one person: Jill Kelley, a 37-year-old Tampa socialite who hosted parties for the nation's top military brass.

Kelley's complaint about anonymous, threatening email triggered the FBI investigation that led to Petraeus' downfall. And now she is at the center of an investigation of the top U.S. commander in Afghanistan over alleged "inappropriate communications" between the two.

Kelley is a close friend of the Petraeus family, and photographs circulating in the media show the dark-haired woman at parties with Petraeus, his wife, and Kelley's husband, Scott, a cancer surgeon. She served as a sort of unofficial social ambassador for U.S. Central Command in Tampa, holding gatherings for the general when he was commander there from 2008 to 2010.