Inside the fight to take down online prostitution review boards

— -- At first glance, the undercover video captured by a Seattle detective seems to show an ordinary guys' night out -- a bunch of men just hanging out at a local watering hole, eating nachos and drinking beers.

But police said these bar patrons were part of an exclusive group that called itself “The League of Extraordinary Gentlemen,” and they were meeting to talk about a very specific shared interest: their fondness for Korean prostitutes, who they referred to as “k-girls.”

“She’s as close to perfect as I think they get made,” one man said, describing one of the Korean women.

“Right after k-girls, I’ve always had this thing for Eastern Europeans,” another said. “Like Czech, Hungarian, anyone from a war-torn country. Anything with ‘will work for food.’”

Unbeknownst to them, the detective sitting at their table during this series of meet-ups in 2015 was secretly videotaping their conversations as part of an undercover operation.

“Everybody would sit down and order drinks, eat food, and talk about the latest prostitute that they have had sex with and trends that were going on,” the undercover detective told ABC News' “Nightline.” “There were some waitresses that seemed a little offended.”

Watch the full story on ABC News "Nightline" tonight at 12:35 a.m. ET

This unprecedented prostitution sting eventually blew the lid off a secretive network of online review boards – websites where users rate and recommend local prostitutes. King County District Attorney Valiant Richey described these sites as “Yelp for prostitution.”

Prostitution review websites are a prolific corner of the illicit online sex trade. Major websites, like TnA Review and The Erotic Review, cover nearly every city in the United States; each location has its own local customer reviews and often, escort ads. While these websites operate across the country, not all of these online communities agree to meet in person—something that made the Seattle case especially unique.

The investigation resulted in police raiding several brothels in the wealthy Seattle suburb of Bellevue, and the shutdown of three websites: “The Review Board” and its two Korean-centric offshoots, “The League” and “K-Girl Delights.” Something else unique about this case—the controversial felony charge leveled against several of the website users.

“We have charged the people who were putting the content on the website with a felony charge of promoting prostitution,” Richey said.

“Men go on, and they post reviews, and they share information,” he continued. “It goes beyond just a review and then on to a recommendation: ‘You have to go see this person, she's amazing. Go see her before she leaves.’”

Felony charges for what many view as simply posting reviews on a website has never been attempted before in the United States. For Richey, it is part of his philosophy of focusing on the demand side of the prostitution industry, targeting the users instead of the suppliers.

“Most people in prostitution are exploited and so criminalizing them doesn't make a lot of sense from a moral perspective, it also just doesn't work from a criminal justice perspective,” Richey said. “At the same time, we understand … the exploitation that is driven through sex buying, is caused by the buyer. And so the buyer needs to be held accountable.”

Some of the review site users caught in this sting were prominent tech executives, including an Amazon software developer and a high-level Microsoft director. Richey said that many of the men he charged were high-level users, and were “spending anywhere from $30,000 to $50,000 a year on this.”

Critics of Richey’s demand-side prosecution philosophy have accused him of using his office to make headlines, a charge he fully denies.

“The main focus for us is on dismantling these networks of buyers who are creating this vociferous demand for exploited women,” he said.

All of the men charged in this case declined requests for on-the-record interviews. In addition to the website shutdowns, several Korean brothels in Bellevue were raided. Police say they found 12 women of Korean descent inside, who they released without charges. In a police press conference, the women were described as "trafficked." While “Nightline” was unable to track down any of these women, a man who owned two of these brothels agreed to tell his side of the story.

Michael Durnal served 45 days in prison after his Bellevue brothels were raided by police. He said he first became involved in the Korean prostitution world as a client. Then he fell in love with one of the women. The woman was in debt back in Korea, he was told, so Durnal decided to leave his family and his job to open up a brothel with her to make money.

Durnal said his reason for picking Bellevue was simple: “Bellevue's big money.” He ended up opening two brothels there, and said his job was to book clients for the women working in his locations. But Durnal said that as time went on, he began to get to know the women and learn more about why they were selling sex.

“Some of them just want to start a business,” he said. “Some of them, their families will get hurt or, you know, death … One girl actually in particular told me that. I asked her why she doesn't just run and she said she tried, and they find them.”

Durnal repeatedly said he regrets getting involved in prostitution because he said he saw firsthand the damage it could do. “You feel like the piece of the soul from the girl is gone,” he said.

While he said he never personally used “The Review Board” or any similar website, he said many of his clients did.

“I would ask my clients, ‘If you liked her, review her,’ you know?” he said.

Yet Durnal questions the police’s claim that they “rescued” the Korean women in the brothels.

“They said that, ‘People were holding them captive.’ This came out of law enforcement's mouth,” he said. “And who did they save? Every girl they let go? Every girl's back in the business. They just go someplace else.”

“They're moving on their own, they’re not being held captive in what one would think of as being held captive,” Durnal continued. “Nobody is holding their passports.”

Brad Myles of the anti-trafficking group Polaris said debt bondage is a common factor when it comes to Korean women working out of brothels in the United States.

“Debt bondage is different from debt,” Myles said. “It’s a particular kind of predatory manipulative debt, where fees and interest rates and other hidden costs and all these things kick into gear, so … the debt grows faster than the person can pay it off."

He went on, "You’ve got women being recruited from South Korea, usually told lies about what they’re going to be doing here in the United Sates, usually held in some kind of debt. And then you have these customers that are coming and buying sex from these women who think that the women are there voluntarily. But the customers don’t understand the full picture.”

The “Nightline” team met one Seattle-based sex worker, Maggie McNeill, who criticized the shutdown of the review websites, saying they provided a valuable vetting tool for her in booking clients.

“You have [a] reputation,” she said. “To use an example, right, eBay … if somebody's got 98 percent positive reviews on eBay as a buyer or as a seller, that lets you have confidence in dealing with that person.”

McNeill, who also runs a popular sex work blog, said that she believes the shutdown of these boards interferes with free speech, and to shut them down is a disservice both to sex workers and to those exercising their right to free association online.

But Alisa Bernard, who calls herself a prostitution survivor turned activist, said she believes review sites don’t make things safer for sex workers. She used to work through “The Review Board” in the Seattle area.

“There's a perception of safety because there's this, ‘Oh, well, you have to go through this board, and it's online, and look how clean it is,’” Bernard said. “I had been raped multiple times. I was held against my will at least once. I was strangled, and these were all by Review Board guys so, you know, again, your line keeps getting pushed further and further and further to get those good reviews.”

Bernard explained that a bad review could have a huge impact on business, giving the clients too much power.

“Women within prostitution experience rates of PTSD twice that of war veterans,” she said, citing a 1988 study by Dr. Melissa Farley, a psychologist and researcher at the Kaiser-Permanente Medical Center in San Francisco. “This is the reality for us.”

While the controversy over review websites will continue, District Attorney Valiant Richey said he is working to eliminate sex buying altogether, calling prostitution “the oldest oppression.” He travels across the country, telling other prosecutors about demand-side prostitution prosecution and encouraging them to take on similar cases.

“The one way we can try to eliminate it is by helping men realize that this isn't serving them either,” he said. “In a survey of sex buyers, three-quarters of buyers said they wanted to stop. It would be a great step forward in reducing nation-wide exploitation if these review boards did not exist.”