Washington (CNN) -- A Drug Enforcement Administration agent stationed in Cartagena, Colombia, arranged for a prostitute to have an encounter with a U.S. Secret Service Agent only days before a visit there by President Barack Obama, the Justice Department's inspector general has found.
In a December 20 letter to the top Democrat and Republican on the Senate Homeland Security Committee, the inspector general said the agent admitted his role in hiring the woman, while a second DEA agent said he was intoxicated that night and was unable to "recall specifically his involvement."
A third DEA special agent was present for a dinner with the Secret Service agent but was not present at a residence where the sexual encounter took place and played no role in facilitating it, the report said.
All three DEA agents eventually admitted they had paid for sexual services in Colombia, the inspector general said.
The inspector general and a U.S. Attorney determined there was no basis for bringing a criminal charge in the case, but the agents could still face disciplinary action.
The details of the DEA agents' actions were spelled out in a summary that Sen. Susan Collins, R-Maine, on Wednesday forwarded to DEA Administrator Michele Leonhart, expressing concern and demanding to know what was being done.
In a letter, first reported Thursday by NBC News, Collins said she found the matter "troubling."
"Why haven't the administrative actions been completed given that the ... extremely serious findings ... were relayed to DEA more than three months ago?" Collins asked.
The inspector general had no comment, but the Justice Department report indicated the DEA had been informed of the alleged misconduct in September.
Late Thursday, the DEA issued a brief written statement saying, "This matter is currently under review by the Board of Professional Conduct." The DEA said it takes these matters "very seriously."
The Secret Service had no comment.
As part of the advance detail before Obama's arrival to attend an April 2012 summit, a dozen Secret Service agents hit the clubs of Cartagena, for a night of drinking that ended with them bringing women back to their hotel rooms.
Some of the women received money, and others did not ask for any, but in one case, an agent refused to pay, and the woman summoned a police officer.
Nine Secret Service agents implicated in the case resigned or retired. Three were cleared of serious misconduct.
Prostitution is legal in Colombia. But the news that some Secret Service agents were drinking heavily and taking prostitutes back to their hotel rooms raised security concerns and tarnished the reputation of the agency charged with protecting the president.