Washington (CNN) -- A Senate committee will expand its probe into the U.S. Secret Service this week following a scandal involving prostitutes in Colombia in advance of a recent trip by the president. 

The Homeland Security Committee will send the Secret Service "some questions this week, as the beginning of our broader investigation, asking whether... this was an exception, or is there anything in the records that show this is a pattern of misconduct that has gone on elsewhere by Secret Service agents on assignment, but off-duty?" Sen. Joe Lieberman, the committee chairman, told "Fox News Sunday." 

"Why wasn't it noticed if that was the case? What's the Secret Service going to do to make sure it never happens again?" 

Some Secret Service members and agents allegedly brought back several prostitutes to a hotel in Cartagena, according to sources familiar with the U.S. government's investigation. 

The Secret Service says 12 members of the agency have been implicated in the incident. 

Across the Sunday political talk shows, officials expressed confidence in Secret Service Director Mark Sullivan, saying they believe he has handled the scandal well and will get answers. 

"History is full of cases where enemies have compromised" people with security or intelligence information through sex, said Lieberman, I-Connecticut. He added that based on what he has been told so far, "there is no evidence that information was compromised" in this case. 

Down the road, the committee will hold a public hearing on the matter -- perhaps more than one, Lieberman said. 
Who was involved in the scandal?
 prostitutes