MINNEAPOLIS — A 19-year-old woman faces federal charges of recruiting minors for prostitution, after some teenage girls told investigators she was actively recruiting clients for a sex ring she allegedly operated out of a Burnsville motel where she worked.

Investigators believe Justine Alex Reisdorf of Eagan advertised in the “erotic services” section of the Web site Craigslist.org, and more recently on the “Live Links” telephone chat line, according to a statement by FBI agent Lisa Nielsen.

Eagan Police Detective Kurt Bratulich started the investigation in December after a girl who allegedly worked for Reisdorf confided in him.

“I work at one of the schools, so the victim felt pretty comfortable in talking to me about what was going on,” Bratulich said Wednesday. “It kind of snowballed on the state level, and it turned into a federal investigation once we found that the Internet was used and that the victims were underage.”

Bratulich said the FBI is still investigating and investigators and prosecutors met with the defense attorney Wednesday to discuss the case. He declined to say more.

Reisdorf’s attorney, assistant federal defender Katherine Menendez, declined to comment.

Reisdorf, the mother of a 14-month-old girl, was charged June 14 in federal court with recruiting minors for a prostitution ring from November 2006 until June.

According to court documents and statements from Nielsen, Bratulich learned Reisdorf was recruiting high school girls to work for her as prostitutes at a town house she rented in Burnsville. He found advertisements on Craigslist that read: “Hi Fellas. it’s the party girls … 200 roses for 2 hours for one of us … 375 roses for 2 hours for 3 of us … Kandy, Deja and Carmen.” He learned “Deja” was Reisdorf’s alias and “roses” was code for dollars.

Authorities searched the Burnsville residence in December, but Reisdorf was in the process of moving and few items were left, records show.

Nielsen and Bratulich interviewed an underage girl in February who said Reisdorf had run a brothel in the Burnsville town house and advertised the services of adult and minor prostitutes on Craigslist.

Another underage female admitted working for Reisdorf, Nielsen said. The girl also said Reisdorf put ads on Craigslist that contained pictures showing parts of her body.

In April, investigators traced some erotic postings on Craigslist to “Deja A. McDone.” They connected phone numbers in the ads to Reisdorf.

Last month, another juvenile told Bratulich that Reisdorf was “actively recruiting minor children to engage in acts of prostitution,” Nielsen said. The investigation indicated Reisdorf used her job at a Burnsville motel “to obtain hotel rooms for purposes of prostitution,” she said.

Nielsen also said Reisdorf no longer exclusively advertises on Craigslist but solicits prostitution on a telephone chat line known as “Live Links.”