Many foreign-born victims of labor trafficking actually came to the United States legally, according to a study released Tuesday that provides an in-depth look into forced labor.

The study from Urban Institute and Northeastern University draws upon a trove of data, including closed records of 122 victims, as well as interviews with people who had been forced into work, along with police and advocates.

Among their sample, 71 percent had entered the U.S. on valid, temporary visas, but 69 percent of them were unauthorized to be here once they escaped their traffickers. The victims in the study were all immigrants, but one of the lead authors Meredith Dank said “we can’t 100 percent generalize based on that. We know there is labor trafficking of U.S. citizens as well.”

The finding about immigrants’ legal status counters the perception of such workers as  coming to the United States illegally and being unauthorized to work in this country, Dank said. A common tactic among traffickers, the study found, was to hold documents and visas over the workers, so that once the visas expired, they could threaten workers with the possibility of deportation.

“We heard many stories where the traffickers were fairly influential individuals in the community,” Dank said. “One person even said their trafficker was a judge, and when they hosted a dinner, law enforcement were there at the table.”

The type of work varied, from household domestics to restaurant and hotel workers — people working in plain sight. The victims ended up in forced labor through a variety of ways, too. Most in the study hailed from Mexico, the Philippines, India and Turkey, with the majority of people being forced to work in agriculture coming from Latin America. They ended up working throughout the U.S.: in rural, suburban and urban areas.

Most victims in the study, which were almost evenly split between men and women, were recruited in their home countries, and often ended up working for third or fourth-party employment agencies. Victims in the study paid an average of $6,150 in fees to recruiters, a debt that left them stuck in a vicious cycle of exploitation.

In some instances, people being trafficked were “dehumanized” often, a strategy to hold control of them, Dank said. One victim recounted being made to eat the family’s table scraps. “This mental process they go through, it’s almost a form of isolation, like ‘I have to figure this out on my own,'” Dank said.

When it came to the perpetrators, 65 percent of suspects in the study’s sample actually were arrested, but very few victims ever really received restitution.

Given there is no primary entity responsible for labor trafficking investigations (for instance, the Labor Department has no criminal authority), there is gray area and problems with coordinating across various law enforcement agencies, the study found. And even if U.S.-based recruitment agencies do run into legal trouble, they can very easily shut down and reopen as new ones, circumventing any sort of visa blacklist.

Researchers recommend looking at reforms to federal and state laws related to immigration, especially guest worker programs, and making workers’ visas more flexible and not tied to specific employers. Then there’s one major, immediate problem, Dank said: “There isn’t a single shelter in the entire United States dedicated to male trafficking victims,” she said. “Service providers struggle with, where do you put them.”