CBS News) WASHINGTON - U.S. investigators are in Cartagena, Colombia, asking witnesses exactly what happened in the Secret Service sex scandal.
One U.S. senator says up to 20 women were involved with Secret Service agents and military aides in Colombia preparing for last weekend's visit by President Obama.
CBS News has learned that the Secret Service now wants to polygraph the individuals involved in this scandal. A senior law enforcement official says it is just one part of the investigation and that "we want to use every possible tool to get to the bottom of this."
CBS News has also learned that Mr. Obama's security team was partying at a strip club called The Pley just 48 hours before he arrived in Colombia.
The men -- 11 Secret Service and 10 military members -- met as many as 20 foreign women -- some prostitutes -- and reportedly paid them $60 each to go to their Cartagena hotel.
The two highest-ranking U.S. senators on the committee that oversees the Secret Service are receiving briefings on the investigation. They want to know whether national security was jeopardized.
"We don't know what kind of access these women had to highly classified information," says Sen. Susan Collins, R-Me.
"If the allegations are true, people should be punished," said Sen. Joe Lieberman, I-Conn., who added that he's considering holding a hearing on the scandal.
But a top law enforcement official tells CBS News no sensitive information was compromised -- that "these agents had not received a briefing on the president's trip" and would not have had his schedule.
The Pentagon is also investigating. It's looking into the 10 military members involved, including five members of the Army's elite special forces.
And now, the Department of Homeland Security, which oversees the Secret Service, has lauched its own probe.
At the White House, the president's spokesman would not answer questions on whether this is an isolated incident or a pattern behavior.
When asked if the president felt the scandal signals a broader cultural problem, Press Secretary Jay Carney said, "There is an investigation ongoing that we should let take its course before we speculate about its conclusions."
To see Norah O'Donnell's report, click on the video in the player above.