Mystery around David Petraeus scandal deepens as General John Allen tied to Jill Kelley - VIDEO

Gen. John Allen, L, who is being investigated for "inappropriate communications" with unpaid military socialite Jill Kelley, R.

The socialite at the center of the David Petraeus cheating scandal sent thousands of 'inappropriate' emails to top military official General John Allen, it has been revealed.

Tampa resident Jill Kelley has been described as the ‘other woman’ in the scandal that led to the resignation of Army Gen. David Petraeus from his post as CIA director.

News of the scandal broke after Kelley reported she had received email threats from Paula Broadwell, Petraeus' alleged mistress.

After Kelley filed a complaint, FBI agents traced the emails to Paula Broadwell, Petraeus’ biographer. In the course of the investigation agents discovered emails between Petraeus and Broadwell that suggested the pair had an extramarital affair.

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In the latest bizarre twist, the FBI is investigating emails between Kelley and John Allen, the top U.S. General in Afghanistan.

According to ABC News, a Defense Department official said the probe into Allen includes a review of 20,000 to 30,000 emails between the general and Kelley, including some characterized as "inappropriate" and "flirtatious."

Kelley, a 37-year-old mother of three, volunteered her time to support the military. She and her husband, cancer doctor Scott Kelley, planned and hosted charitable events for military personal.

On Sunday, a spokesman issued a statement on behalf of Kelley and her husband, saying: “We and our family have been friends with General Petraeus and his family for over five years. We respect his and his family’s privacy and want the same for us and our three children.”

Jill Kelley's brother, David Khawam, spoke out on her behalf this week also. "I know who my sister is and I know she's a good mother and a good wife," he said. "This is completely uncharacteristic of her to have romantic relationships outside of her marriage."

"The primary thing is that she wants her privacy protected," he added. "I think she'll probably come out and make a statement at one point."

What the CBS News report below: