Former CIA Director David Petraeus\' female biographer allegedly sent harassing emails to a woman, causing the investigation that ended his job, the FBI said. Petraeus, 60, resigned this week after admitting he \"showed extremely poor judgment by engaging in an extramarital affair\" with his 40-year-old biographer, Paula Broadwell. Sources who didn\'t want to be identified told CNN the FBI opened an investigation when an unidentified woman close to Petraeus complained Broadwell was sending her abusive emails. The New York Times said the recipient of the emails was neither a family member nor a government employee, the newspaper said. Petraeus was scheduled to testify Thursday about the Sept. 11 attack on the U.S. Consulate in Benghazi, Libya, that killed four Americans. Instead, acting CIA Director Michael Morell will speak to the Senate Intelligence Committee. That doesn\'t sit well with Homeland Security Committee Chairman Rep. Peter King, R-N.Y., CNN said. \"David Petraeus\' testifying has nothing to do with whether or not he\'s still the CIA director, and I don\'t see how the CIA can say he\'s not going to testify,\" King said. \"He was at the center of this, and he has answers that only he has.\"