A 60-year-old former massage worker from Taiwan, who agreed to be identified only by the nickname she commonly uses, Tina, said she was lured into working at a massage parlor in New York a decade ago by the travel agency broker who helped secure her visa to travel to the United States. “People come here and don’t have a place to live,” she said. “These places offer a place to live, and it seems like a nice idea. They say, ‘It’s not safe to keep your passport on hand,’ and they will ask to hold the passport.”

She was arrested several times before getting out of the business, and feels comparatively lucky. One close friend was spirited to Texas by traffickers, she said, had her passport taken and was forced to see eight to 12 customers a day. One day the tearful calls she often received from her friend came to an abrupt halt.

“A lot of the businesses that look like either nail salons or massage places, especially the places that offer massage, there are bad things happening there,” she said. “It’s 100 percent organized crime.”

The ubiquity of the massage parlors offers an accessibility and sheen of normalcy not offered by traditional brothels. And as the massage parlors have expanded even into small-town America in recent years, meticulously detailed review sites like Rubmaps have served as the Yelp and Foursquare of the illicit parlor business, with graphic anatomical descriptions of the women and explicit breakdowns of the sexual services proffered.

Even at illicit parlors, owners and managers can claim ignorance of the additional services offered by employees behind closed doors. The evidence gathered during raids and searches often tells a far different tale. The police say it is common to find ledgers tracking the number of “dates” women have had, as was found in a bust in Dallas in 2016. In one case in Kansas, a search of the premises yielded a notebook with handwritten Chinese-English translations that “included sexually explicit phrases such as ‘did you bring condom’ and ‘happy ending.’”

A federal law enforcement official, speaking on the condition of anonymity because this person is involved in active cases, said that the most common method for smuggling women from Asian countries was either a fraudulent tourist visa or a fraudulent work visa, such as for nursing work. Many came as students, then overstayed to work in the sex industry.

Many women arrive in the United States from China bearing heavy debt burdens and try to find work in restaurants or nail salons. But the money isn’t good enough for the five-figure debts weighing them down. The massage jobs are presented as opportunities for fast, easy money.