ST. CLOUD -- Sex trafficking is a growing industry among gangs and drug dealers who use women to make them money by selling sex. It's a crime syndicate that operates in the shadows of every city, big and small and Stearns County cities are no different.

A national push to cut down on trafficking people for sex has led to increased investigations and prosecutions. In fact, six area police departments collaborated in 2012 to form a sex trafficking task force to jail those who traffic women, charge those who buy sex and give sex-trafficked girls a way out.

Stearns County Attorney Janelle Kendall says pimps have learned they can make a lot of money by controlling women and using them to make money.

These are drug dealers who have gone into a more profitable line of work. You can sell drugs once a day. You can sell a person multiple times a day. It was very eye-opening that it's going on right here, right now.

According to the Stearns County Attorney's Office, St. Cloud is number two in the state behind the Twin Cities in the number of ads for sex. Authorities have also learned St. Cloud is a "training ground" for pimps looking to traffic women for sex.  The reasons are numerous.  Waite Park Police Sergeant Tim Deschene says women are sent to St. Cloud where the competition is less than in the Twin Cities.  St. Cloud is also along the I-94 corridor where men traffic women up to Fargo and to the Bakken oil fields.

Kendall says it's a very profitable business...

These are criminals who've been criminals for a long time, but this is a profitable St. Cloud...hundreds of calls a day coming in for one ad put up on

The sex trafficking is intertwined with drug sales, guns and gangs.  Waite Park Police Chief Dave Bentrud says the prostitution is often tied to benefit a gang, making it organized crime.

The Central Minnesota Sex Trafficking Task Force has been seeing some success from their efforts. All 100 cases of men looking to buy sex have led to convictions.  And, there have been at least three convictions of men who were trafficking women with more awaiting court hearings.

Those on the front lines are trying to help the women and girls leave their pimps and get out of that life.  But, it isn't easy.  Many women are abused, are hooked on drugs, distrust police, and don't have a place to go.

There are resources for juveniles who are trafficked. The Safe Harbor Law provides housing and resources for victims. But, many of those resources aren't available for adults who want to leave. Advocates at the Central Minnesota Sexual Assault Center do what they can to help women find resources and get the counseling they need to start a new life, but as long as demand for paid sex remains, there will always be men who are victimizing women in order to provide the supply.

Videographers Alex Svejkovsky and Isaac Schweer contributed to this story.