What began as a simple observation by local authorities — Thai women being shuttled between apartments and hotels around the Twin Cities — evolved into a federal takedown of a massive international sex trafficking ring, with nearly a dozen arrests and multiple indictments announced Wednesday.

Seventeen people, including several Minnesotans and 12 Thai nationals, are being charged in an alleged scheme that stretched across the Pacific Ocean.

The charges, announced Wednesday in Minneapolis, say the conspirators transported hundreds of young Thai women with fraudulent visas to the United States to become "modern-day sex slaves."

Authorities say the charges mark a major blow to the enterprise, hitting multiple layers of its hierarchy, including a Thai ringleader who was already in custody in Belgium on separate trafficking charges.

Agents fanned out across the United States on Tuesday to round up defendants, including some in the Twin Cities, and will seek the extradition of the group's boss, Sumalee Intarathong, 55, from Belgium.

"What makes this particular case so significant is that global impact, how large this network was," said Alex Khu, special agent in charge for U.S. Homeland Security Investigations. "We're talking about pretty much all of the major metropolitan hubs — so the reach of this organization is massive."

Charges include numerous conspiracy counts of sex trafficking, forced labor, money laundering and visa fraud. U.S. Attorney Andrew Luger said co-conspirators ran a "highly sophisticated" scheme that promised the women a better life in America but instead "forced them to live a nightmare."

It is the ninth trafficking case charged since Luger created a human trafficking initiative in 2014, but the first to target an entire enterprise, drawing national attention.

"This takes us to a different level," said Sen. Amy Klobuchar, DFL-Minn., on Wednesday. "You can go after the small-scale ones, which is important, but if that's all you do you're not really fixing the problem."

'Bondage debts'

According to a 35-page indictment returned under seal by a federal grand jury last week, the conspiracy dated to at least 2009 and targeted nearly a dozen U.S. cities, including Minneapolis, Los Angeles, Chicago, Las Vegas and Washington, D.C. Authorities are still working to identify more victims, but early estimates were in the "hundreds."

Intarathong recruited women in Thailand, made them pose for professional-quality escort photos to advertise online, and encouraged them to undergo breast augmentation surgery to better appeal to U.S. customers, the indictment said. The victims carried "bondage debts" of $40,000 to $60,000 apiece — including the cost of their transport across the Pacific Ocean — which they would be forced to pay off through commercial sex acts.

The women, called "flowers" by their traffickers, were made to have sex with strangers for as long as 12 hours a day nearly every day of the week. They came from impoverished backgrounds and spoke little English, officials said. Traffickers also gathered details about their relatives to threaten them if the women tried to flee, according to the indictment.

Intarathong also served as a "house boss" alongside three other defendants in Minneapolis, Atlanta, Phoenix and Chicago — running daily operations out of apartments, hotels, houses or massage parlors.

Five more "facilitators" named in the indictment helped with tasks like booking travel and advertising victims online. An alleged "facilitator" was Supapon Sonprasit, 31, of St. Paul, one of several co-defendants who also began as a victim before rising within the organization to help traffic others. Four "runners" — including John Zbaracki, 59, of Lakeville — accompanied victims at all times and were paid, in part, in sex with the victims.

Four others remain at large and are not thought to be in Minnesota, Luger said.

Feds will also purse 'johns'

The organization operated at least seven locations and trafficked more than a dozen victims throughout Minnesota. Zbaracki met one victim at Minneapolis-St. Paul Airport, drove to Bloomington to buy condoms and food before forcing her to work out of a Bloomington apartment, according to the indictment. She was later trafficked to Arizona and Indiana.

Authorities vowed Wednesday that the demand side of the conspiracy won't escape unscathed, with state and local law enforcement agencies targeting "johns" through regular sting operations.

"Thousands, if not tens of thousands of men financed ... this organization over the years as customers," Luger said. "The men who purchased sex from an organization such as this are supporting the denial of rights and freedoms to women who have been tricked, abused and coerced."

Beatríz Menanteau, an attorney with the Advocates for Human Rights in Minneapolis, noted "an extensive need" for services to help victims of the sex trade. "The immediate needs like housing, medical, interpretive and immigration services support," she said. "And the long-term view: What are they going to need for the extreme trauma they faced?"

Women's advocates noted that the sting also underlines the ease with which traffickers advertise sex on websites like backpage.com and eros.com — as victims in this case were advertised.

Terry Williams, vice president of the Women's Foundation of Minnesota, said 35,000 ads for the sale of young women around the Twin Cities were posted on backpage.com in the first half of this year.

Meanwhile, in a statement Wednesday, U.S. Attorney General Loretta Lynch highlighted the case as a demonstration of the Justice Department's push to hold traffickers accountable and help victims "reclaim their freedom and dignity."

Klobuchar, who spoke on human trafficking at the Democratic National Convention and has sponsored several pieces of legislation on the subject, said Washington officials like Lynch have committed to making the cases a priority.

"If we're going to change how we view women across the world," Klobuchar said, "the U.S. has to be a beacon of protecting the human rights of women."

Twitter: @smontemayor