The Secret Service on Wednesday announced the departure of three employees connected to a prostitution scandal last week involving members of President Obama’s security detail who were in Cartagena, Colombia.

As the agency tried to manage the fallout from the embarrassing episode, it said in a statement that one agent is expected to resign and another, a supervisor, intends to retire. A third, also a supervisor, has been recommended for firing but will have an opportunity to appeal, officials said.

In all, 11 Secret Service employees — either agents or staff members of the agency’s uniformed division — and 10 military personnel are suspected of being involved in a night of carousing that included heavy drinking, visits to strip clubs and prostitutes on April 11, two nights before Obama was to arrive in the seaside town of Cartagena for an international summit.

The agency and the Defense Department are each investigating the alleged misconduct. The remaining eight Secret Service personnel are on administrative leave, and their top-secret security clearances have been suspended. The military has returned its service members to their home bases.

“We demand that all of our employees adhere to the highest professional and ethical standards and are committed to a full review of this matter,” the Secret Service said in a statement.

Sen. Mary Landrieu (D-La.), chairman of the Senate Appropriations subcommittee on homeland security, called the men’s alleged misbehavior a “gross violation of public trust.”

The allegations — and accompanying negative publicity — have deeply angered rank-and-file members of the Secret Service, severely lowering morale at the agency.

In interviews, current and former agents said they are particularly outraged by the alleged involvement of the two senior supervisors, both of whom have two decades of experience and were sent on the trip to oversee the less-experienced members of the team. Both of those supervisors have spent significant time on presidential protective details, dating to the Clinton administration, according to current and former agents. The two are based in Washington.

“I was really disappointed. I’ve learned a lot from both of these guys,” said one agent, who spoke on the condition of anonymity because he was not authorized to talk to reporters. “I was surprised they were involved. Especially because they are senior people.”

Those familiar with details of the investigation said the two supervisors were sent to Cartagena as leaders of Secret Service “jump teams,” squads made up of several dozen special agents and uniformed officers that are deployed to a site in the days before the president arrives.

It is customary for the jump teams to fly aboard giant Lockheed military transport aircraft, nicknamed “car planes,” which also carry the presidential limousine, Chevy Suburbans and other vehicles that make up the president’s motorcade.

Several of the agents reportedly were part of the elite counter-assault team, which reports to the special operations division, not the presidential protective detail. The rest were uniformed officers who work with bomb-sniffing dogs or magnetometers.

When members of the group arrived in Cartagena, they joined an advance team of White House staff, military and Secret Service members and U.S. Embassy officials that had been on the ground for two weeks, holding nightly “countdown meetings” to mark their planning progress.

But for the Secret Service agents and officers on the car planes, who were among the last to arrive, there wasn’t a lot to do before Obama showed up, according to people familiar with the trip.

The advance team had developed a plan, and it would be up to the car-plane guys to implement it once Air Force One touched down.

So, for a day or two, the men had ample downtime — amid a handful of planning meetings and rehearsal walk-throughs — to eat at restaurants, hit the hotel gym and explore the Cartagena night life.

“That may be one reason these guys felt they were not on duty until the president arrived,” said a retired agent who has been heavily involved in Secret Service training over the years. “They just didn’t have anything to do.”

On the night of April 11, at least some of the men spent time at the Pleyclub, a strip club where they paid for the services of at least two women, according to people in Cartagena who are familiar with details of the evening. They took the women back to the Hotel Ca­ribe, where the advance team was staying. All 21 Secret Service and military personnel are suspected of having had women in their rooms that night. Prostitution is legal and regulated in Colombia, but agency rules prohibit employees from engaging in immoral conduct.

The following morning, however, one of the agents got into a dispute with one of the women over payment, drawing the attention of the hotel staff and Colombian police, who reported the incident to the U.S. Embassy.

Current and former Secret Service personnel said in interviews that they were angered by the damage the scandal has done to the agency’s reputation and the embarrassment it has caused the Obama administration.

At the same time, they lamented the prospect of losing the experience of the two supervisors in an election year and the strain such a loss will put on the agency. The Secret Service has a $1.5 billion budget, 3,500 agents and 1,400 uniformed officers.

Last fiscal year, agents shadowed high-level U.S. officials on more than 5,600 domestic and nearly 400 international trips. This year is expected to be even busier with the presidential campaign in full swing.

“I’m just shocked this happened. We were instructed never to party — even on our own time,” said Bill Holland, who worked as a uniformed division officer during the Nixon administration. But he acknowledged that the agency’s assignments have become far more demanding over the years, requiring uniformed service officers to travel and do advance work far more often than in the past.

Obama’s relentless travel schedule during the election season contributes to that, he said, and can lead staff members to feel the need to “blow off steam.”

“The more the president travels, the more the pressure builds,” Holland said. “They live under a lot of pressure every day. He is a traveling president. He is on the road all the time. Is it an excuse? No. No way.”

Staff writer Ed O’Keefe and staff researchers Alice Crites and Lucy Shackelford contributed to this report.