Rep. Darrell Issa (R-Calif.) said that the Secret Service scandal in Colombia could be larger than the 11 agents who were placed on administrative leave Saturday.

Issa, who chairs the House Oversight and Government Reform Committee, said on CBS’s “Face the Nation” Sunday that the scandal, which allegedly involved prostitutes in Colombia, was probably not the first of its kind.

“Things like this don’t happen once,” Issa said. “We think the number might be higher. We’re asking for the exact amount of all people ‘involved.’ ”

Issa said his committee will be looking “over the shoulder” of the investigation into the misconduct, saying he did not know whether he’d hold hearings yet.