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Homeland Security Secretary Janet Napolitano said Wednesday that a former Secret Service agent's Facebook post in which he claimed to be ogling Sarah Palin was "unacceptable and unprofessional."

The posting came to light after the agent, supervisor David Chaney, was forced to resign following the prostitution scandal in Colombia. In a photo showing him looking at the then-GOP vice presidential nominee, Chaney wrote that he was "really checking her out."

Napolitano discussed the agent and other aspects of the prostitution scandal during testimony Wednesday before a Senate committee on Capitol Hill. She said she had no knowledge of any similar incident over the past two-and-a-half years, and that the alleged April 11-12 incident posed "no risk" to President Obama, who arrived later for the Summit of the Americas.

Napolitano also said the Office of Inspector General is overseeing the agency's internal investigation and that the administration will "leave no stone unturned" as it probes the matter. She said the administration will fix any systemic problems that might turn up.

The secretary testified after the Service announced more disciplinary measures Tuesday evening, forcing out two more employees and permanently revoking the security clearance of a third.

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    In addition, two other Secret Service employees were cleared of serious misconduct, which concludes the investigation of the agency employees so far identified in the scandal. In total, nine have been forced out or had their clearances stripped and three have been cleared of serious misconduct.

    Napolitano testified Wednesday that she doesn't have any evidence any member of Obama's White House team was involved in the scandal.

    GOP Sen. Charles Grassley, though, has pressed the White House for more information on that question -- after the White House declared its internal review had cleared White House staff of any misconduct.

    Grassley, ranking member of the Senate Judiciary Committee, also raised the concern that U.S. agents could have exposed themselves to a spy-world honeypot scheme -- though there is no indication that the women involved in Colombia were working for any foreign government.

    "We're looking at something that is very, very serious when national security might not be protected properly," Grassley told RadioIowa. "Who knows who might be using prostitutes? The Russians are famous for that to get information out of us. You want to know that the president is protected."