WASHINGTON – Members of Congress said Sunday they want to know more details about the FBI investigation that revealed an extramarital affair between ex-CIA Director David Petraeus and his biographer, questioning when the retired general popped up in the FBI inquiry, whether national security was compromised and why they weren't told sooner.

"We received no advanced notice. It was like a lightning bolt," said Democratic Sen. Dianne Feinstein of California, who heads the Senate Intelligence Committee.

The FBI was investigating harassing emails sent by Petraeus biographer and girlfriend Paula Broadwell to a second woman. That probe of Broadwell's emails revealed the affair between Broadwell and Petraeus. The FBI contacted Petraeus and other intelligence officials, and Director of National Intelligence James Clapper asked Petraeus to resign.