SIOUX FALLS, S.D. -

As part of a national sting called 'Operation Cross Country', Sioux Falls Police arrested a woman for prostitution over the weekend.

The operation was funded by the FBI to help catch human traffickers. Police say their street crimes unit answered an online ad on Saturday and arranged to meet two women in the southwest part of town.

Police say 20-year-old Meairra Wilson of Milwaukee, Wisconsin and a 15-year-old girl showed up. They say Wilson arranged for the two to come to Sioux Falls. They took a train and a bus to get here.

Police say they didn't have enough to charge Wilson with coersion or human trafficking. Wilson is charged with prostitution, pimping, promoting prostitution and sexual exploitation of a minor.

The minor was not reported missing or as a runaway. She is being held until relatives can come and get her.