NBC: Prostitute's $50 fee for two agents triggered Secret Service scandal MSNBC's Thomas Roberts speaks with NBC National Investigative Correspondent Michael Isikoff and former Secret Service agent and current Senate candidate Dan Bongino about the fallout from the Secret Service prostitution scandal. By Michael Isikoff and Jim Miklaszewski, NBC News The Colombian prostitute who triggered the scandal that has rocked the Secret Service got angry with two agents who refused to pay her full price for servicing the two of them, leading to a financial dispute over between $40 and $60, according to a government source who has been briefed on the investigation. Two agents from the service's elite Counter Assault Team, in Cartagena, Colombia, in advance of President Barack Obama's arrival for the Summit of the Americas over the weekend, had procured the women's services at a local strip club called the Pley Club on the evening of April 11. All the Secret Service agents and officers implicated in the scandal are believed to have gone to the club that evening and brought back women, a U.S. official told NBC News. The controversy arose after one of the women went back to a hotel room with two agents. The woman wanted to be paid for serving both agents, the source who has been briefed on the probe told NBC News. Instead, the agents would only agree to split her price, prompting the woman to complain to local police who were stationed in the lobby of the Caribe Hotel, the source said. The police then went up to the agents' room and began banging on the door, which the agents at first refused to open, the source said. There are conflicting reports over how the payment dispute was resolved. But two government sources told NBC News the police contacted the U.S. Embassy over the dispute and Embassy officials then arrived at the scene. All those with booked rooms at the hotel had to pay a fee of $25 for bringing any guests to their rooms -- and the guests were required to leave some form of identification at the front desk. A quick scan of the hotel register by a U.S. Embassy official established that 11 Secret Service agents had brought back women to their rooms that evening. When Embassy officials notified Secret Service Director Mark Sullivan, he immediately ordered all the agents to fly home, the sources said. The Secret Service members -- including agents and uniformed officers -- were stripped of their security clearances on Monday. Included in that group were two high-level Secret Service supervisors, three counter assault officers whose job is to repel attacks and three sniper-team members, who take to rooftops to secure areas where the president might visit, NBC News reported. U.S. officials have described the agents' conduct as a potential security breach especially because all the agents involved had access to the president's day-by-day, minute-by-minute schedule. But one official familiar with the security arrangements said that there were no specific security threats during the president's trip. Although agents upon arrival were briefed about current activities by leftist FARC guerrillas and local drug cartels, they were told neither had made any specific threats to the president. The only specific security concern mentioned was that agents and officers were told to bar a left-wing journalist from events at the summit and were given a flier with the journalist's photograph to keep him out, the law enforcement source said. The Secret Service sent agents to Colombia to interview the prostitutes who hooked up Americans to figure out if the women are under age, involved with terrorism or trafficking in illegal drugs, a lawmaker told NBC News' Luke Russert on Tuesday. "They have all their IDs and are conducting an extensive background check to make sure they aren't affiliated with any narcotrafficking or terrorist group or that they could be minors," Homeland Security chairman Rep. Peter King told Russert. So far there is no security breach. King, who was briefed on the Colombia investigation by Sullivan, confirmed that there were 11 agents and 11 women. "The investigation could take a while simply because of the amount of women involved," King said. Some are saying they were prostitutes and others say they weren't. U.S. military officials told NBC News on Tuesday that 10 American servicemen also were under investigation. According to the officials that includes five Army soldiers, two Navy sailors, two Marines and one Air Force airman. One military official says it appears that at least two of the service members were found with prostitutes in their hotel rooms, the same el Caribe where the Secret Service detail stayed. It's not clear whether any of the military members were in any way connected to the allegations involving members of the Secret Service at a Cartagena strip club. It's also not yet clear whether any of the 10 will face criminal charges. House and Senate lawmakers are also looking into the allegations. King told The Associated Press that his committee is devoting four investigators to the probe. Meanwhile, one former Secret Service agent, Dan Bongino who is a Republican candidate for Congress in Maryland, told NBC News that in his 12 years at the agency he never saw anything like what is alleged to have taken place in Colombia. I'm not saying it's never happened, but I never saw it. Bongino said. He denied there was a culture of partying inside the agency. A decade ago, however, U.S. News and World Report published an investigative report detailing criminal activity and extreme partying as well as oversight problems. In one reported incident, members of Vice President Dick Cheney's security detail got into a brawl outside a bar on a trip to the San Diego area. As the agency sought to rebuild its image, other high-profile incidents with presidential protection brought more scrutiny. In 2008, an Iraqi journalist threw shoes at President George W. Bush during a Baghdad visit. And in November 2009 three people crashed a White House state dinner for Indian Prime Minister Manmohan Singh. Michaele and Tareq Salahi and Carlos Allen were able to get past Secret Security agents at the door and enter the party. The Salahis even met Obama and had their picture taken with Vice President Joe Biden. In a January 2010 congressional hearing on the matter, the Salahis, who have since divorced, refused to testify, invoking their Fifth Amendment right against self-incrimination. The prostitution scandal, however, has brought far more intense focus on the Secret Service and behavior by its agents and officers. "This really is the biggest scandal in the history of the Secret Service," Ron Kessler, author of "In the President's Secret Service," told NBC News earlier this week. He said the agency's problems are deeply rooted. "There's a culture in the Secret Service that's fostered by the management of just nodding, winking, favoritism," he said. What the agency needs is an outside director who can come in, clean house, change the standards. Michael Isikoff is NBC News' national investigative correspondent; Jim Miklaszewski is NBC News' chief Pentagon correspondent. NBC News Correspondent Luke Russert and msnbc.com reporter Jeff Black also contributed to this report.