WASHINGTON - The chairman of a House committee investigating an alleged Secret Service prostitution scandal predicted more firings as key lawmakers and a top adviser to President Obama expressed confidence Sunday that the agency will effectively deal with the incident.

"Every possible lead is being examined," said Rep. Peter King (R., N.Y.), who heads the House Homeland Security Committee. King said he expected that in the "near future, several other" members of the Secret Service will leave.

"What they were thinking is beyond me," King told NBC's Meet the Press.

So far, the scandal includes 12 Secret Service employees and 11 military members.

Six of the Secret Service members have lost their jobs. One has been cleared and five remain on administrative leave. The main incident occurred shortly before Obama arrived for a meeting of regional presidents last weekend.

A Secret Service official confirmed Sunday that one of the 12 implicated in the scandal was not staying at the same hotel as the others. He was staying at the Hilton, where Obama would stay, said the official, who spoke on condition of anonymity because the official was not authorized to discuss the matter publicly. The agent is being investigated in a separate incident that may have happened April 9, days before the president arrived and while the hotel was still open to the general public.

Sen. Joe Lieberman, chairman of the Senate Homeland Security and Government Affairs Committee, also mentioned the 12th agent under investigation in an appearance on CBS's Face the Nation.

"Now we don't know at this point what that 12th agent is being charged with and why he's been put on administrative leave. But now you're into the hotel where the president of the United States was going to stay. And it just gets more troubling," Lieberman said.

Lieberman told Fox News Sunday that there was "no evidence that information was compromised." Those involved "were not acting like Secret Service agents. They were acting like a bunch of college students away on a spring student weekend," Lieberman said.

King, Lieberman, and other leaders of congressional committees examining the scandal made the rounds on Sunday news shows. Generally, they said the scandal was being closely scrutinized on Capitol Hill and voiced support for Secret Service Director Mark Sullivan's handling of the matter.

Obama campaign adviser David Axelrod said the allegations are disturbing, but the misdeeds of a few should not tarnish the overall work and reputation of the service.

Axelrod told CNN's State of the Union that he always felt the agents were willing to go to great lengths to protect the president and those around him. He called the conduct in Colombia disappointing.

Sen. Tom Coburn (R., Okla.), a frequent Obama critic, told CBS: "I'm not critical of what the administration has done thus far." He termed the Colombia incident "an aberration."

Sen. Susan Collins of Maine, the senior Republican on the Homeland Security Committee, and Rep. Carolyn Maloney (D., N.Y.) both said that more female Secret Service agents might help guard against such incidents.