They are the stern-faced agents, earphones in place, eyes scouring crowds for potential threats, who accompany US leaders across the world to protect their safety. But an advance party of Secret Service agents deployed to oversee security for President Barack Obama's visit to Colombia this weekend also apparently found time to pursue some local diversions.
About 12 agents are now embroiled in a prostitution scandal after at least one woman complained to police in the city of Cartagena, which is hosting the Summit of the Americas, that she had not been paid.
There were claims that the elite presidential bodyguards, some of whom are married and including at least two supervisors, had brought prostitutes back to their hotel, which is also housing US delegation members and media.
Another report said only one agent had returned to his room with a prostitute, but that Secret Service chiefs decided to recall all the members of the team so they could be questioned by internal agency investigators about his behaviour and security issues.
"This is the worst scandal in the history of the agency," said Ronald Kessler, author of In The President's Secret Service, who broke the story after receiving a tip from an agency source. Although prostitution is legal in Colombia inside so-called "tolerance zones", the agents could still have been exposed to blackmail and the business is closely connected to crime and drug gangs. About a dozen men have now been sent home.
The Colombian police contacted American diplomats, who tried to mediate the dispute and keep a lid on the crisis as a new crew of agents were rushed to the country. US officials insisted that there was no danger to Mr Obama and that the agents had already been replaced by the time he arrived in Cartagena on Friday evening.
But two explosions from home-made pipe-bombs in the city on Friday evening and two more blasts in the capital in Bogota, were a reminder of the security dangers in Colombia. Despite marked improvements in recent years, the country has long been plagued by far-Left political terrorism, drug cartel violence and kidnappings.
"This is a very bad security breach and is being taken extremely seriously inside the agency," Mr Kessler said. "Aside from the morality issues, even if prostitution is legal, this conduct opened these men up to the threat of blackmail. Terrorists could have gained access to secure areas and that could have resulted in an assassination attempt. The consequences could have been extremely serious".
The incident also threatened to overshadow Mr Obama's efforts to focus on the economy and boosting trade ties with Latin America. With Hispanic voters in the US crucial to his re-election hopes in November, Mr Obama has been keen to use the three-day summit to show he is engaged in a region that critics have accused him of largely ignoring.
In an interview with a Spanish language television station, he courted Hispanic voters back home by saying that he would purse immigration reform in his second term and attacking Mitt Romney, his presumed Republican rival, for his policies.
Colombian media reported that prostitutes descended on Cartagena ahead of the summit, where heads of state and delegations from 34 of the hemisphere's 35 countries - Cuba is absent - are discussing trade, the economy and regional co-operation.
The agents were staying at the Hotel Caribe, which is also hosting members of the White House staff and press corps during the summit. A hotel employee said the agents arrived at the beachfront hotel about a week ago, and alleged that they were drinking heavily during their stay.
The employee said the agents left the hotel on Thursday, a day before Mr Obama and other regional leaders arrived for the weekend summit. Edwin Donovan, a Secret Service spokesman, said the agency's Office of Professional Responsibility, which serves as its internal affairs unit, was investigating the men's actions.
"The Secret Service takes all allegations of misconduct seriously," Mr Donovan said. "These personnel changes will not affect the comprehensive security plan that has been prepared in advance of the President's trip."
Daniel Bongino, a former Secret Service agent with the presidential protection division who left the agency last year and is now running for a US Senate seat, said that he was told the team had all been told to report to internal affairs.
"I am hearing that it's an isolated incident, that it's one individual who had some interaction with a prostitute," he told The New York Times. "A confrontation ensued, and it didn't end well."
The scandal is the latest embarrassment for the agency under the Obama administration. In a major breach of security that shocked Washington, three party-crashers talked their way past Secret Service agents into a White House state dinner hosted by the president in 2009, despite not having an invitation.
In August, a Secret Service agent was arrested for drunken driving in Iowa, where he was arranging security for a visit by Mr Obama. The agent, who was off duty at the time, was recently sentenced to two days in jail and fined $US1250.
On the eve of the summit, Radio Cadena Nacional (RCN), a leading Colombian station, broadcast a special feature about the "thriving and well-organised" prostitution racket in Cartagena.
The programme featured interviews with local taxi drivers who take visitors to areas where they could find women. Once the price - usually about 80,000 Colombian pesos ($45) - had been negotiated, they drove the couple to a secluded area or to a network of residences where rooms could be rented by the hour.
"All the prostitutes are heading to Cartagena for the summit," one woman told the station.
Source