Three U.S. Drug Enforcement Administration agents are under investigation for misconduct for allegedly hiring prostitutes in Cartagena, Colombia, according to media sources.

The Justice Department Inspector General's Office is investigating the alleged misconduct, which is not said to be related to the Secret Service scandal last month in Colombia. The information that led to the investigation came from Secret Service agents themselves.

A dozen Secret Service agents were implicated in that prostitution scandal and several have been fired or have retired as a result. The Secret Service incident happened ahead of President Barack Obama's visit for the Summit of the Americas meeting.

A dozen military personnel are also being investigated for that incident.

Reports are that the incident involving the DEA occurred around the same time the Secret Service agents were in Colombia. The DEA told the Associated Press that information gleaned from the Secret Service sparked the probe into its agency.

Sources familiar with the investigation told CBS News that the allegations were brought against the DEA by a Secret Service agent questioned by investigators.

DEA takes allegations of misconduct very seriously and will take appropriate personnel action, if warranted, upon the conclusion of the [Office of Inspector General] investigation, DEA spokesman Rusty Payne said in a statement.

Sen. Susan Collins, the top Republican on the Homeland Security Committee, told Reuters in a statement that female foreign national masseuses were apparently entertained in one of the agents' apartments in Cartagena.

Collins was informed of the incident on May 4, but she didn't comment until the employees were removed from the country and questioned.

It's disturbing that we may be uncovering a troubling culture that spans more than one law enforcement agency, said Collins. The evidence uncovered thus far indicates that this likely was not just a one-time incident.

The DEA has permanent offices in Colombia. Prostitution is legal in that country.