Minneapolis police and federal agents busted a prostitution operation Thursday involving more than 100 Asian women brought illegally into the United States who put an estimated $70,000 a month into the ringleader's pocket.

The case is the first time Minneapolis police and the federal Immigration and Customs Enforcement (ICE) agency have partnered for a long-term criminal investigation. It started about a year ago, when an ICE special agent learned of an illegal sex business in south Minneapolis.

Since then, the operation moved frequently, from a house in north Minneapolis to hotels in Bloomington. The women, all Chinese or Korean, were brought in from Las Vegas, Flushing, N.Y., and Los Angeles, working a couple of weeks before moving on. The ring currently ran from a massage parlor in Minneapolis' Uptown neighborhood and a posh apartment complex in St. Louis Park.

It's unclear if the ringleader, a Chinese national who has not yet been charged, had other brothels, but police have identified at least a dozen similar operations in the Twin Cities.

"This is the face of human trafficking in Minnesota," said Sgt. Grant Snyder, one of the lead investigators. "It's no longer just the image people have of women chained to beds or being smuggled into the country hidden in boats. [Still,] the women in this ring were most likely coerced in some way."

Most clients were white, upper-class men between ages 35 and 55, Snyder said. They included doctors, people celebrating birthdays and a Wisconsin business owner. The starting price was usually $80, all of which went to the leader. Any money earned by the women came through negotiations behind closed doors.

"Some were forced to the United States illegally to pay off debts," said Sgt. Matt Wente, another lead investigator. "Others came willingly for financial opportunities not possible in their homeland, but then got drawn in a prostitution network that is difficult to escape."

The four women found during Thursday's raids weren't arrested. Instead, representatives from the Jerry Vick Task Force, which works with crime victims, was on hand to help them find social services and temporary housing.

'Not a 911 crime'

Last year, the Legislature commissioned the first state report on human trafficking, which found that 43 percent of the 119 human service providers it surveyed had helped a victim of human trafficking -- and that they were helping about 200 victims at the time of the survey.

"It's not a 911 crime," Wente said. "Who reports it to police?"

Snyder said the women weren't allowed to leave the place of business. They would sleep on a couch or a massage table. They often spoke no English, and passports or other forms of identification were taken away, he said. The ringleader kept them under video surveillance.

According to police, one woman had worked in Minneapolis three previous times. Another paid $15,000 to have someone smuggle her across the border from Canada. The ringleader, who police say often picked up the women at the airport, ran a similar business in California before police forced him out of the state. Police said he planned to open other brothels outside of Minnesota.

The Twin Cities businesses were listed daily on Craigslist or in local U.S. and Chinese newspapers. They even distributed fliers, Snyder said.

To take down such operations, police focus on the leaders and anybody profiting from the women, said Capt. Dave Hayhoe. The intensive investigation included undercover visits and tracing financial documents and bank accounts. Customers were stopped and asked questions by officers when they left the businesses.

The case was opened by ICE special agent Jeremy Christenson, and he remained on throughout the investigation. The Minneapolis Police Department also was assisted by the Bureau of Criminal Apprehension and St. Paul police. The ringleader was arrested in St. Paul for suspicion of promoting prostitution and could face state or federal charges, and more arrests could follow, Snyder said.

"This was a very successful case, and we hope to do more in the future," said ICE spokesman Tim Counts.

Earlier this year, Minneapolis police took heat for assisting immigration agents during a prostitution bust because city policy prevents officers from involvement in routine immigration enforcement. Snyder wanted to make it clear this case was about criminal activity, not immigration issues.

The nameless Minneapolis location at 515 W. Lake Street is tucked into a small strip of businesses. The word "massage" in red letters is taped on the front door. A waving ceramic cat greets customers in the lobby.

The property owner said his tenant showed him a license that allowed the business to offer massages. They moved in about eight months ago, and he hasn't received any complaints.

Andrew Notermann, an agent at the nearby La Progresiva insurance agency, said he only saw the alleged manager of the massage business when she came in their office to adjust the thermostat shared by building tenants. When he learned about the prostitution allegation, he repeatedly said, "You got to be kidding me."

"It's pretty sickening it is so close to us," he said.

The brothel operation in St. Louis Park was at 4755 Park Commons Drive. An employee of a south Minneapolis restaurant falsified documents saying that the ringleader worked as a chef, which allowed him to rent the apartment, Snyder said. Apartment management cooperated with the investigation, he said.

Customers continued to seek a massage at the Minneapolis location Thursday, even with officers standing in the lobby. After taking out boxes of evidence and $6,500, Snyder turned off the neon "open" sign in the window and locked the door.

David Chanen • 612-673-4465