“We have no reason to believe anything else happened, but we want to have a complete and thorough investigation to ensure this didn’t go any further,” said the senior official, who has been briefed on the inquiry and spoke on the condition of anonymity because the investigation was continuing.
The official said the widening inquiry included a review of agency personnel who had rooms at the Hilton Cartagena, where Mr. Obama and Secretary of State Hillary Rodham Clinton stayed, as well as the Hotel Caribe, where the 11 agents and several military officers implicated in the scandal had rooms.
“They’re now talking to everyone,” the senior official said. “We’re taking this one step at a time.”
The official also confirmed the identities of two Secret Service supervisors involved who were dismissed on Thursday. Greg Stokes, who worked with a canine unit, was fired. The other, David Chaney, was allowed to retire. The supervisors were previously identified by CBS News.
In Washington, Representative Peter T. King, Republican of New York and chairman of the House Homeland Security Committee, said people at the Secret Service had told him that “more agents are expected to be leaving.”
Meanwhile, in Colombia, a lawyer retained by the woman who got into a dispute with a Secret Service agent over how much he owed her for sex said Thursday that she would cooperate with any official inquiries. The lawyer, Marlon Betancourt, said in an interview in Cartagena, where the suspected misconduct took place, that he had not been contacted by the United States or the Colombian authorities.
The woman, who has left Cartagena, was also looking into taking legal action against Secret Service personnel and the American government because, she said, the agent acted aggressively toward her, yelling and using an expletive to describe her, according to Mr. Betancourt.
“I believe that laws were broken here,” he said. “You cannot mistreat people.”
The woman, a single mother, has described herself as a high-class escort who charges as much as $800 to have sex with men, and Mr. Betancourt said she was seeking to sell her story.
“It’s not about making money,” he said. “It’s about seeking some kind of compensation for what has happened.”
He added, “Her life is not going to be the same as it was before.”
At least one of the 11 Secret Service employees under scrutiny has told investigators that he had not known that the woman he had spent the night with was a prostitute, according to another senior government official briefed on the investigation.
The employee, whom the official did not identify, has offered to take a lie-detector test.
That account appeared to be bolstered by one of the women involved in the scandal who said that while she had spent the night with one of the Secret Service employees in his room at the Hotel Caribe, they had not had sex and she had not been paid.
“I didn’t talk with him about money,“ said the woman, who asked that her name not be used.
“My guy never touched me,” she said. “He never gave me a kiss or anything.”
Breaking down in tears, the woman, 22, said she was not a prostitute and described how a night on the town had blown up into an international scandal.
She said she had gone to the hotel with one of the agents only to accompany a friend who she said was a prostitute. She described the man she had been with as very “timid” and said they both had fallen asleep with their clothes on shortly after they had gone to his room at the Hotel Caribe.
She also questioned news accounts that said a large number of Secret Service agents had taken women to their rooms, saying that when the dispute over money broke out the next morning, the other Americans were surprised that an agent had taken a prostitute to the hotel.
“They didn’t know,” she said. “That’s why I think this is unfair.”
Her account was largely corroborated by versions of the story told by her friend, the prostitute; by a taxi driver who drove the women home from the hotel; and by American officials briefed on the investigation.
But the woman contradicted a key part of her friend’s story, saying the friend had asked to be paid only $250 to $300 for sex, not the $800 she asserted in an interview with The New York Times.
While the Secret Service employee may be able to prove that he did not knowingly get involved with a prostitute, that would probably not save his job.
Defense lawyers and current and former government officials said the men under scrutiny may well lose their jobs because their behavior would cost them the security clearance needed to work for the Secret Service.
“It is the classic way and easiest way to fire someone,” said Stephen M. Kohn, the head of the National Whistleblowers Center in Washington, which often represents government employees who face disciplinary action. “For security clearance you have to have a high level of trust and not have associations or relationships that could compromise you. For the government, if you don’t pay your loans or have an affair, you are susceptible to blackmail” and can lose your security clearance.
“If you don’t have security clearance,” Mr. Kohn added, “you are usually on the street in 90 days without a job.”
The military is moving forward with its own investigation. Col. Scott Malcom, the chief spokesman for United States Southern Command in Miami, said 10 enlisted members of the military were being scrutinized: 5 Army Special Forces soldiers, 2 members of the Navy, 2 Marines and 1 member of the Air Force.
It is not yet clear whether any of the military members hired prostitutes, Colonel Malcom said.
If they did, they would have violated the Uniform Code of Military Justice, which prohibits service members from soliciting prostitutes. Penalties for such an infraction can include a dishonorable discharge and time in military prison.
