U.S. Sen. Dick Durbin says questions must be asked of the CIA director that stepped down after acknowledging he had an affair. (Photo used under Creative Commons from Flickr user AMSF 2011)

By Nick Gale and Metro News Service

WASHINGTON, D.C. - Members of Congress are demanding more details on how and when the FBI learned of the extramarital affair that led to the resignation of CIA Director David Petraeus.

U.S. Sen. Dick Durbin (D-Ill.) said it's a tragedy for the Petraeus family, but said questions have to be asked.

"They will be about whether any kind of classified information was transmitted to this person that he had an affair with and I think those questions need to be asked for the record,” Durbin said.

Petraeus told National Intelligence Director James Clapper about the situation last Tuesday, Election Day. The White House said it first learned of the affair on Wednesday, and President Obama accepted Petraeus' resignation Friday.

Congressional leaders who found out just hours before the public learned of the resignation want to know why the FBI didn't inform them sooner about the investigation into Petraeus and Paula Broadwell, the woman he was having the affair with. They also want to know why the FBI didn't notify the White House it was investigating the CIA director.

A former spokesman for Petraeus said the retired general's affair with a female biographer started after Petraeus left the Army.

Petraeus had been scheduled to testify on Tuesday about the CIA investigation into the attack of the U.S. diplomatic post in Benghazi, Libya. U.S. Sen. Dianne Feinstein, the top Democrat on intelligence issues, said there was absolutely no connection between Petraeus' resignation and the Benghazi attack.

Durbin said the nation needs answers on that, too.

“We have every right to ask the questions,” Durbin said. "Four Americans lost their lives there and we need to find out who’s responsible and hold them accountable for it.”