A nondescript massage parlor in the heart of Buffalo, Minn., has been the target of a yearlong human trafficking investigation, and authorities say they plan to bring charges soon.

On Dec. 6, eight Buffalo police officers and members of the Minnesota Bureau of Criminal Apprehension raided the Sunshing Spa massage parlor at 404 7th St. NE.

The parlor promoted deep tissue, hot stone and infrared therapies in a sign on its storefront window.

A 53-year-old woman was arrested for solicitation for prostitution, and is suspected of being involved in the operation, said Buffalo Police Chief Pat Budke. Another 52-year-old woman was arrested for disorderly conduct. She is not believed to be involved with the operation.

Both women were interviewed but neither was charged.

Mandy Erickson, a graphic designer who works at Precision Prints nearby, said she saw part of the raid unfold. "We saw six or seven unmarked cars pull up," she said. Then she saw a policewoman with some handcuffs head for the building. "As soon as I saw an officer, I figured out what was happening," she said.

"This is a small town," she said. "People were surprised."

The massage parlor closed down on the day of the raid and has not opened since. People were seen entering the storefront and hauling away furniture and equipment — some of which was set out on the sidewalk with a sign that said it was free to take. The spa now looks to be completely empty.

Budke predicted charges will likely be filed against the owners, operators and managers, but declined to say when they would be brought.

The spa opened in August 2016 in a small business mall that includes an auto body shop in the back, several other businesses and a picture frame shop in front. Within a couple of months, police received a report of suspicious activity.

"A citizen entered the business and saw employees scantily clad and made a complaint that they suspected something was going on," Budke said. "They suspected there was sex trafficking."

The business became the subject of discussion at two Buffalo City Council meetings, Budke said.

"Buffalo is very much a bedroom community," Budke said. "It has a small-town feel. There is no tolerance on the part of the community for this."

Doug Selle, owner of Radio-Active Mobile Electronics a short distance away, recalls a customer coming into his store to buy a mobile car starter. He said the customer told him he had seen the massage parlor and thought he'd go over and get a massage while the starter was being installed.

When the customer returned, he told Selle that the massage therapist had propositioned him.

"We had heard rumors about what was going on in there," said Selle.

With the help of the BCA, Buffalo police launched a probe that included undercover work and surveillance.

The nature of the investigation is difficult, said Budke, because the massage therapists engaging in prostitution are viewed as the victims, not the target of criminal charges.

"The focus has to be the people who are running the trafficking," he said. "It takes time to build enough intelligence to do a search warrant."

The search warrant has been sealed, but Budke said officers were looking for information that included "financial documentation, who's running the business, what's the nature of the business, where is the money coming, where is the money going."

The two women who were arrested could not be reached for comment.

Randy Furst • 651-925-5043 Twitter: @randyfurst