Lawmakers briefed on the investigation say more firings are likely imminent.
And we've now learned the names of some agents involved.
More Secret Service agents involved in the prostitution scandal in Colombia could resign or be fired as early as today , according to New York Congressman Peter King (R-NY).
"Director Sullivan has said that as soon as he believes he has sufficient evidence to require someone to leave he will act," King said.
Three agents have already been forced out.
Supervisor David Chaney retired.
Greg Stokes , who ran the canine unit was removed with cause , but can appeal.
A third agent resigned , and eight more are still under investigation.
The agents are accused of hiring prostitutes and bringing them back to their hotel in Cartayna last week.
They were in Colombia setting up security for President Obama's trip to the Summit of the Americas.
The Secret Service is updating congressmen about the investigations underway here in Washington and in Colombia. Lawmakers are expressing their outrage about what happened.
"This is unacceptable behavior," said Sen. Jeff Sessions (R-AL)
"Those people who are responsible have brought disgrace and it's disgusting," said former House Speaker Nancy Pelosi (D-CA).
Pelosi says agents need to be held accountable. "I don't see how those who are involved in this should be able to continue in their work."
White House Spokesman Jay Carney says the President still has confidence in the Director of the Secret Service and the agency. "He has high regard for and great appreciation for the extraordinary work that the Secret Service does to protect him, his family, those who travel with him."
The Secret Service says the actions of its agents never compromised the President's security.
The investigators sent to Colombia are from the Secret Service and the military.
10 members of the military are also being investigated for their involvement.
(Susan McGinnis, CBS News)