People walk past Hotel El Caribe in Cartagena, Colombia, last Saturday. Secret Service personnel implicated in the prostitution scandal stayed there in advance of President Obama’s arrival. (Fernando Vergara/AP)

Senate Homeland Security and Governmental Affairs Committee Chairman Joseph I. Lieberman (I-Conn.) said it was a reasonable question to ask whether White House staffers sent to Colombia were involved in the scandal and urged the Obama administration to conduct an investigation “just to make sure that none of them were involved.”

“The White House advance person knows exactly where the president is going to be at any time,” Lieberman said on “Fox News Sunday.” “If anybody thinking the worst wanted to attack the President of the United States, one of the ways he might find out the path that he would follow in Cartagena is by compromising White House advance personnel.”

On Friday, Sen. Charles E. Grassley (R-Iowa) urged the Secret Service to broaden its investigation to determine which White House advance staff and communications personnel were in Colombia before Obama’s arrival and whether they knew anything about the scandal.

There has been no evidence of White House staff involvement in the night of heavy drinking and interactions with prostitutes that led to the scandal, and Grassley’s aides declined to say whether the senator has learned of specific incidents involving White House personnel.

At least four congressional committees are receiving daily briefings from Secret Service officials as the investigation continues and the House Oversight and Government Reform Committee and the House Homeland Security Committee have made formal requests for full information on the scandal by as early as Friday. Though no committee has scheduled a hearing to explore the scandal itself, Homeland Security Secretary Janet Napolitano is scheduled to testify Wednesday at a Senate Judiciary Committee hearing on general oversight matters at the Department of Homeland Security, which oversees the Secret Service.

On Sunday, lawmakers said they expect more Secret Service employees involved in the scandal to leave soon, while Lieberman and other lawmakers also continued to voice amazement at the agents’ risky behavior.

“From what we know, they were not acting like Secret Service agents, they were acting like a bunch of college students on spring weekend,” Lieberman told Fox.

“I think we have some bad actors here, but I don’t think that we judge the Secret Service by its weakest link,” Rep. Elijah Cummings (D-Md.) told CNN’s “State of the Union,” adding later that “You can’t legislate people not being stupid, but certainly you can uphold the high standards of this organization.”

Cummings is the ranking Democrat on the House oversight panel. He and other lawmakers continued to back Secret Service Director Mark Sullivan.

“I have full confidence in him,” said House Homeland Security Committee Chairman Peter King (R-N.Y.), who also told NBC’s “Meet the Press” that “From every indication I’ve seen, from the moment this scandal broke until now, there’s no attempt to cover anything over. Everything possible lead is being examined.”

House Oversight and Government Reform Committee Chairman Darrell Issa (R-Calif.) also expressed support for Sullivan, but told NBC that “The most important thing for all of us is, this never happen again or anything like it, because it could someday lead to a compromise if it isn’t fixed.”

Two other lawmakers suggested the scandal could have been avoided if the Secret Service employed more women.

“I can’t help but wonder if there’d been more women as part of that detail if this ever would’ve happened,” said Sen. Susan Collins (Maine), ranking Republican on the Senate homeland security panel.

Appearing with Collins on ABC’s “This Week,” Rep. Carolyn Maloney (D-N.Y.) agreed, noting that just 11 percent of Secret Service employees are female.

“I can’t help but keep asking this question: where are the women,” Maloney said. “We probably need to diversify the Secret Service, and have more minorities and more women.”

Maloney is a member of the House Oversight and Government Reform Committee.

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