Homeland Security Secretary Janet Napolitano is facing questions Wednesday from a Senate panel on the Secret Service prostitution scandal that embarrassed the White House and overshadowed the president's visit to a Latin American summit.

The Secret Service says two more of those implicated have been ousted, one stripped of his clearance and two cleared, resolving questions about the fates of the full dozen under investigation.

Judiciary Committee Chairman Patrick Leahy said he wants to know how thorough the investigation into the misconduct has been and whether such behavior by agents has been tolerated in the past.

"I think that's a very legitimate question. And I've raised it twice with the director of the Secret Service. We'll raise it again," Leahy said on NBC's "Today Show."

Other senators, particularly Republicans, had big plans for the televised hearing, the first public proceedings expected to touch on the scandal. The Secret Service announced late Tuesday that all 12 implicated had been dealt with: nine forced out, one stripped of his security clearance and two cleared of wrongdoing, all within two weeks of the night in question.

The scandal erupted after a fight over payment between a Colombian prostitute and a Secret Service employee spilled into the hallway of the Hotel Caribe ahead of President Barack Obama's arrival at the Summit of the Americas in Cartagena. A dozen military personnel have also been implicated, and Defense Secretary Leon Panetta said they have had their security clearances suspended.

Further stealing his critics' thunder, Obama said Tuesday the employees at the center of the scandal were not representative of the agency that protects his family in the glare of public life. "These guys are incredible. They protect me. They protect Michelle. They protect the girls. They protect our officials all around the world," the president said on NBC's "Late Night With Jimmy Fallon."

"A couple of knuckleheads shouldn't detract from what they do," Obama added. "What these guys were thinking, I don't know. That's why they're not there anymore."

Some of the Judiciary Committee members still had questions. Ranking Republican Charles Grassley of Iowa, for example, wants to know whether Napolitano's inspector general has opened an independent investigation. Lawmakers across Congress say they are concerned about the security risk posed by the proximity the prostitutes — as many as 20, all foreign nationals — had to personnel with sensitive information on the president's plans.

"No one wants to see the president's security compromised or America embarrassed," Leahy was expected to say to Napolitano, according to his prepared remarks.

The Colombia scandal has been widely denounced by official Washington, but it's a delicate political matter in an election year with the presidency and congressional majorities at stake. All sides have praised Secret Service Director Mark Sullivan's swift action and thorough investigation, in part because he's spent significant time keeping key lawmakers in the loop. Pentagon officials, too, are investigating and are expected to brief Senate Armed Services Committee Chairman Carl Levin and ranking Republican John McCain on Wednesday.

In a similar but unrelated incident, Panetta said Tuesday that three Marines on a U.S. Embassy security team and one embassy staff member were punished for allegedly pushing a prostitute out of a car in Brasilia, Brazil, last year after a dispute over payment. Panetta, speaking in Brasilia, said he had "no tolerance for that kind of conduct."

A senior defense official, speaking on condition of anonymity to discuss an investigation, said that in the wake of the Cartagena scandal the woman involved in the Brasilia incident has hired a lawyer and is suing the embassy. The official said the woman broke her collarbone when she was pushed from the car.

The military investigation into the Cartagena incident is continuing.

Another Senate panel is looking for a pattern of misconduct. Sen. Joe Lieberman, chairman of the Homeland Security and Governmental Affairs Committee, told reporters on Tuesday that he'll hold hearings on the service's culture and whether clear rules exist on how agents should behave when they are off duty but on assignment.

"You think they wouldn't need that but maybe they do," Lieberman said. He added that his investigators are taking a longer view and beginning to follow up on tips that "whistle-blower people" have called in. He declined to provide details.

"I want to ask questions about whether there is any other evidence of misconduct by Secret Service agents in the last five or 10 years," Lieberman said. "If so, what was done about it, could something have been done to have prevented what happened in Cartagena? And now that it has happened, what do they intend to do?"


Associated Press Writers Ben Feller, Jim Kuhnhenn and Donna Cassata in Washington and Lolita C. Baldor in Brasilia, Brazil, contributed to this report.