CIA launches internal probe of Petraeus' conduct

WASHINGTON (CNN) -- In another twist in the scandal engulfing former CIA chief David Petraeus, the spy agency's internal watchdog is opening an investigation of his conduct while serving as director.

"At the CIA we are constantly reviewing our performance. If there are lessons to be learned from this case we'll use them to improve. But we're not getting ahead of ourselves; an investigation is exploratory and doesn't presuppose any particular outcome," said CIA Spokesman Preston Golson.

The investigation will be led by the CIA Inspector General's office.

Petraeus resigned last Friday as CIA director, citing an extramarital affair. According to his friends, the former four-star general began an affair with his biographer, Paula Broadwell, shortly after taking over at the agency last fall after a distinguished military career.

The announcement of the internal review comes ahead of Petraeus' appearance before the House and Senate Intelligence committees on Friday for testimony on the deadly terror attack in September on the U.S. diplomatic mission in Benghazi, Libya.

The Obama administration has come under close scrutiny from congressional lawmakers over its response to the attack -- both as it was unfolding and in the days immediately following.

U.S. Ambassador Christopher Stevens and three other Americans were killed in the assault.