A Cottage Grove townhouse less than a half-mile from an elementary school served as a brothel where women were forced to make a minimum $800 a day as prostitutes, prosecutors allege.

Washington County Attorney Pete Orput and Ramsey County Attorney John Choi announced Wednesday the arrest of a man who ran the brothel and others in the Twin Cities and North Dakota. His apprehension is part of a major sex trafficking bust that involved multiple East Metro law enforcement agencies. Orput's office is heading up the investigation, which is still active.

"When police entered they saw two beds," Orput said. "They also saw a line of guys waiting on a couch, waiting their turn. Sort of sounds like the damn barbershop, doesn't it, where you're lined up waiting for your haircut? It's that awful."

Dongzhou Jiang, 28, of Blaine is one of four Chinese nationals each charged with six felony counts relating to the transport and exploitation of vulnerable foreign women across 29 states.

Jiang is in custody and facing multiple racketeering and sex charges, which were filed in Washington County District Court.

Also charged are Hong Nmn Jing, Sophia Wang Navas and Fangyao Wu. The three women are in custody and awaiting extradition from Irvine, California, where prosecutors allege their operation was based. Jing and Wu are mother and daughter, according to the complaint.

Also in the complaint, Jing and Navas are referred to by Jiang as "boss ladies" of the organization. They allegedly posted thousands of advertisements on the Backpage website and communicated with all prospective customers. Jing also arranged for the victims to fly to various locations around the country.

"Men would be given the address of the closest place," he said. "It seem to be this was the Uber of sex trafficking, where you can get out your cellphone and you can order up a human being and they'll find a location for you to meet."

The charges are the result of a multi-jurisdictional, two-year investigation by Washington and Ramsey counties that also involved the efforts of the Cottage Grove, Minneapolis, Oakdale, St. Paul and Woodbury police departments. They were assisted by law enforcement in Orange County, Calif.

Two of the female victims are Korean nationals, Orput said. The complaint identified others as Chinese nationals from New York and California.

Six are listed only by their initials in the complaint.

"As someone who has been deeply involved in the fight against sex trafficking in the state of Minnesota, I want to say this is the most sophisticated human trafficking operation I have ever seen," Choi said.

Sophisticated but brutal: The female victims, Choi said, often were raped, beaten or robbed by their customers. They spoke little or no English. Their captors moved them frequently so they couldn't establish ties to any community.

They were also charged $20 a day for housing and $40 each time they were moved, according to the criminal complaint. Orput described Jiang as the "regional manager" of operations in Minnesota and North Dakota. He helped coordinate the purchase or rental of hotels, apartments or houses that were used for sex trafficking, including one location in Oakdale and two in Maplewood, according to the complaint.

"He was in charge of picking up the women, taking them to the different sites, collecting the money, getting them cases of condoms, cases of wet wipes, kind of coordinating the logistics of running this thing," Orput said.

The beatings and assaults were "just part of the business," Jiang told authorities, according to the criminal complaint. A search of his residence turned up $36,000 in cash in different manilla envelopes, each marked with a woman's name.

Woodbury detective Paul Kroshus discovered the Cottage Grove brothel through a phone number listed in a Backpage ad. Law enforcement from Cottage Grove, Oakdale and Woodbury executed a search warrant Feb. 22. They found three Asian females, none of whom spoke English. A garbage can in the garage contained “hundreds” of used condoms.

The major crimes unit of Orput's office combed through over 18,000 ads on Backpage and other sites. The recent shutting down of the escorts section of Backpage has made little difference, said Imran Ali, the assistant attorney in charge of the unit.

"What's happened is that activity that was posted on the escort section actually moved to another area of Backpage," he said.

Orput said there could be more arrests and more victims.

No one is living in the townhome on Hemingway Avenue, a neighbor said.

A sign on the door said: "Please remove your shoes."