The Secret Service says that new evidence has been discovered, linking 11 personnel to alleged misconduct with prostitutes in Colombia last weekend before President Obama arrived for a meeting, the New York Times reported.
Agents allegedly took women to their hotel rooms before the president arrived for a summit meeting in Colombia last weekend.
Investigators are planning on interviewing the women involved in the case, which includes snipers and other agents who handle explosives.
Around 20 women were brought into the hotel, and many made it into agents' hotel rooms.
Senator Susan Collins of Maine, the senior Republican on the Homeland Security Comittee, said that she feared the women might have ties to groups that are hostile with the United States.
"Could they have planted bugs, disabled weapons, or in any others jeopardized security of the president or our country?" Collins said she had asked of the Secret Service.
Nine military personnel are also under investigation, the Washington Post reported.