TAMPA, Fla. (AP) — The Tampa FBI agent who prompted the investigation that resulted in CIA Director David Petraeus' resignation is no stranger to the limelight.

FBI Special Agent Frederick Humphries II played a key role in stopping a terrorist attack aimed at blowing up Los Angeles International Airport just as the year 2000 dawned. He also fatally shot a man who threatened him and other law enforcement officers with a knife during an altercation at Tampa's MacDill Air Force Base in 2010.

Humphries was the agent who initially saw the emails Petraeus' biographer, Paula Broadwell, sent to Tampa socialite Julie Kelley. Humphries thought the emails raised serious concerns because the anonymous author knew the comings and goings of Petraeus and Gen. John Allen, the top U.S. commander in Afghanistan.

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