CARTAGENA, Colombia -- Colombian authorities have opened a preliminary investigation into the U.S. Secret Service prostitution scandal out of concern that underage women might have been involved, a Colombian government official told McClatchy on Friday.

Investigators from the Colombian attorney general’s office have talked with employees of the hotel where the Secret Service agents were staying and have also questioned the taxi driver who drove home the woman whose complaint about not being adequately paid triggered the scandal, the official said. The official was not authorized to discuss the investigation and asked not to be indentified by name.

Police also went to at least one of the adult entertainment clubs linked to the scandal to verify the ages of the women who worked there, a club employee said.

The Colombian probe into the ages of the women for the first time raises the possibility that some of the 21 Americans tied to the scandal _ 11 Secret Service agents and 10 members of the U.S. military _ could face criminal charges in Colombia, and not just ethics complaints within their agencies in the United States. While sex for pay is legal between adults in Colombia, inducing a minor to engage in prostitution is illegal, the official said. As many as 21 women may have provided sexual services to the visiting Americans.

Two Secret Service supervisors have been forced to retire since the scandal broke and a third is expected to be fired. The 10 members of the military face disciplinary action. The men were in Cartagena as an advance team preparing for President Barack Obama’s attendance at a summit of Western Hemisphere leaders last week.

Neither the club employee nor the attorney general’s office would comment on the record about the investigation or the police operation at the Pleyclub, one of the late-night clubs linked to the scandal.

“Prostitution that involves adults is not a crime in Colombia, but inducing minors to engage in prostitution is a crime and this is the reason why the government is trying to verify whether underage women participated in this,” the official said.

So far, she added, officials have not found any evidence of any minors involved in the incident. One of the ways investigators have verified the women’s ages was by examining information the hotel gathered from their identification cards, which women staying overnight at the hotel are required to leave at the reception desk.

Hotel executives and workers have refused to talk about the case.

The Colombian official denied reports that investigators had raided the nightclubs where young women work, but an employee at the Pleyclub said police officers had entered the club late Thursday to check women’s ages.

In Colombia, a person 18 years and older is considered an adult.

The scandal began in the early morning of Thursday, April 12, when a woman, identified as Dania Suarez, complained loudly in a hallway of the Caribe Hotel that the man who had hired her for sex had not paid her the agreed price of $800.

After police officers and hotel personnel responded, the woman apparently received some more money and left the hotel to return home in a cab from the hotel stand.

The driver, who’s been identified as Jose Pena, was not available for comment Friday. He was interviewed at the attorney general’s office in Cartagena earlier in the day, officials confirmed.