Source: Ousted Secret Service agent plans to sue

(CBS News) One of the Secret Service agents who has been forced out of his job is already planning a lawsuit, a congressional aide told CBS News after Mark Sullivan, the agency's director, briefed lawmakers Wednesday night.

Officials are still in the early stages of their investigation, but three of the 11 Secret Service members accused of misconduct have already been forced out. One agent was fired, another forced to retire. Both were supervisors. A third officer resigned.

An agency statement late Wednesday said the remaining eight agents will stay on administrative leave, with their security clearances suspended, as the investigation continues.

The 11 agents and 10 military personnel are accused of hiring prostitutes and engaging in other questionable behavior just before the president's trip to Colombia last week.

In Cartagena, Colombia, one woman, an escort, spoke out to The New York Times about the incident at the hotel there.

Times reporter William Neuman told CBS News, "In the morning, she tries to collect the money and says he must pay her $800, and he says, apparently, 'No way.' And they argue, he gets angry, calls her a name, and kicks her out."

A former head of the agency said Wednesday that it's "exactly right" to say the Secret Service needs to wrap up the investigation quickly to save its reputation.

Former Secret Service director Brian Stafford has protected six presidents. He says the agency is looking to conduct a fair but swift investigation. "The Secret Service," he says, "wants to get it behind them probably more than anybody else does at this point. I mean -- this attention is negative, and it's not good, and is not reflective of the Secret Service and its people."

Officials from the agency spent another day on Capitol Hill Wednesday answering questions from lawmakers looking for decisive action.

"Heads have to roll," said Sen. Charles Grassley, R-Iowa. "If people aren't fired in this town, nothing changes."

Secret Service officials are concerned that the Colombia incident isn't isolated and is part of a possible pattern of behavior when agents go overseas on business.

To see Norah O'Donnell's report, click on the video in the player above.