Prosecutors say the sex trafficking operation involved large numbers of victims and multiple communities throughout the state, the St. Paul (Minn.) Pioneer Press reported Thursday.
Announcing the arrests, Ramsey County Attorney John J. Choi said one witness told investigators the ring preyed on women and girls who were "mentally slow and vulnerable."
Choi said the men also had held two other women as sex slaves, and that more victims may be discovered as his investigation continues.
One victim told police the men convinced the women to be prostitutes by becoming their boyfriends and then telling them they would do it "if you really love me."
Once the victims were found, the ring placed hundreds of ads for them on websites, the prosecutor said.
Eight email addresses, 30 phone numbers and more than 100 pre-paid credit cards were used in the scheme, Choi said.
He said the victims' willingness to talk to investigators had been crucial to the investigation.
The ring is believed to have operated between September 2010 and July 2012.
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