WASHINGTON (CNN) -- Officials warned that more Secret Service resignations could come Friday, stemming from an alleged prostitution scandal in Colombia that is the focus of congressional inquiry and outrage.
Secret Service Director Mark Sullivan has ordered a "comprehensive" investigation of everything that happened during the trip to Cartagena as part of President Barack Obama's protection detail at last week's Summit of the Americas, a source close to the investigation told CNN on Friday.
That includes interviews with every Secret Service member on the trip, hotel staff and alleged prostitutes, the source said. In addition, the source confirmed that Secret Service agents were staying at a second hotel on the trip, which presumably will be included in the expanded probe.
Three agents already have left the service in connection with the alleged heavy drinking and consorting with hookers, including a man who joked on Facebook that he checked out former vice presidential candidate Sarah Palin while on assignment during the 2008 campaign.
The controversy has embarrassed the nearly 150-year-old agency that protects the president and investigates criminal activity, and raised questions of a possible security breach immediately preceding Obama's visit to Colombia.
Another concern is that the alleged heavy drinking and consorting with prostitutes could be part of the culture of agency, in contrast with its agents' reputation for dedication and discipline.
Two Secret Service supervisors no longer with the agency in the wake of the incident were identified as David Chaney and Greg Stokes, a source familiar with the investigation told CNN national security contributor Fran Townsend on Thursday.
In a photo posted on his public Facebook page in January 2009, Chaney is seen standing behind Palin, wearing dark glasses and what appears be a wedding ring.
Under the photo, Chaney posted a comment that said, "I was really checking her out, if you know what I mean?" That drew a strong response from Palin on Thursday night.
"This agent who was kind of ridiculous there in posting pictures and comments about checking someone out," Palin said on Fox News. "Check this out, bodyguard. You're fired! And I hope his wife sends him to the doghouse."
Chaney and Stokes are among the 11 Secret Service employees that the agency has linked to the scandal so far. Eight are on administrative leave, and another also has left the agency.
Further resignations, presumably by some of the eight agency workers on leave, could occur Friday, said Rep. Peter King, R-New York, chairman of the House Homeland Security Committee.
Chaney, a son of a Secret Service agent, has been employed with the agency since 1987, according to his posting on Reunion.com. The posting notes that he is married, has an adopted son and his assignments included a stint protecting former Vice President Dick Cheney.
Stokes supervised the canine training unit at the Secret Service's James J. Rowley Training Center outside Washington, according to PetLife Radio and a career development posting on the University of Maryland's website.
Attorney Lawrence Berger told CNN that he is representing Chaney and Stokes but declined further comment. Berger is general counsel for the Federal Law Enforcement Officers Association, a union that includes the Secret Service, among other agencies.
Authorities outside Chaney's home in Ashburn, Virginia, said he was unwilling to speak to reporters Thursday night.
According to the Secret Service, one of the agents involved in the Colombia incident is a supervisor being allowed to retire, and another supervisor is being forced out, while a third agent resigned.
The supervisor being forced out plans to fight his ouster, a U.S. official said on condition of not being identified. However, it was not immediately clear if that is Chaney or Stokes.
The eight other agency members allegedly involved in the scandal are on administrative leave and have had their security clearances suspended, according to the Secret Service.
In addition, 10 U.S. military personnel are also being investigated in a separate probe for their possible participation.
All the employees are accused of bringing prostitutes to Cartagena's Hotel El Caribe ahead of last week's visit by Obama, who was there to attend the Pan-American summit.
According to sources, the alleged prostitutes -- the youngest of whom were in their early 20s -- had all signed in at the hotel, where the Secret Service members apparently stayed, flashing their local ID cards.
One of these women allegedly was later involved in a dispute about how much she was to be paid for the night, which brought the entire incident to light and sparked controversy in the United States and Colombia.
According to Townsend, the Secret Service agents were part of the "jump team" that flies in on military transport planes with the presidential limousine and other vehicles to be used in the president's motorcade.
They arrived the morning of the incident, raising questions about whether the activity was planned.
Despite concerns that contact with Colombian nationals could have led to security breaches regarding Obama's activities in the South American nation, King said that "from everything we know, nothing was compromised."
Former Colombian President Alvaro Uribe told CNN on Thursday that the incident was due entirely to "a lack of ethics (on the part of) the Secret Service of the United States."
Members of the U.S. Congress offered similarly biting remarks.
House Minority Leader Nancy Pelosi, D-California, called the allegations "disgusting," while Senate Majority Leader Harry Reid described the agents' alleged actions as "either really stupid or a total lack of common sense."
The military investigation involves five members of America's elite Army Special Forces, or Green Berets, plus two people from the Navy, two from the Marines and one from the Air Force, officials said.
The Green Berets' failure to make curfew the night of the incident involving the Secret Service agents led the military to start its investigation, a U.S. official told CNN.
All the military personnel are being investigated for heavy drinking and use of prostitutes while in Colombia as part of the support team for Obama's visit, the official said. They are not likely to redeploy until the matter is resolved, other military officials said, though no formal order bars their deployment.
The military investigation could end with no action, administrative action such as a letter of reprimand or a recommendation to proceed with criminal charges, officials said.
While soliciting prostitution is in most cases legal for adults in Colombia, it is considered a breach of the Secret Service's conduct code, government sources said. Military law also bars service members from patronizing prostitutes, engaging in conduct unbecoming an officer or, for enlisted personnel, conduct "prejudicial to good order and discipline."
CNN's Brian Todd, Bob Kovach, John King, Barbara Starr, Deirdre Walsh, Rafael Romo, Jessica Yellin and Tom Cohen contributed to this report.