Seoul(CNN) A group of Brazilian women who traveled to South Korea hoping to join its multibillion-dollar K-pop industry instead found themselves trafficked into prostitution, according to South Korean police.

Seven Brazilian women in their 20s and 30s were rescued from brothels after police raids last month, and five people were arrested on suspicion of arranging prostitution and trafficking women.

The women were lured to South Korea in early July, after connecting with a man on social media who offered them a free, round-trip flight ticket, a police spokesman said.

"(The) women were told they could be models, or that they would be supported to become K-pop singers," he added.

But once they arrived in South Korea, it was a different story. The women's passports were allegedly taken from them, and they were locked in two houses in Ilsan and Paju, two cities north of Seoul. They were then allegedly sold to a massage parlor for 2 million won ($1,650) each, police said.

Police were tipped off to their situation last month, after a Brazilian woman called her embassy in South Korea asking to be rescued. Officers then raided a massage parlor in Ilsan, where they rescued three Brazilian women.

A few days later, police rescued four more women from a house in Paju. The women were moved to a shelter and seemed "traumatized," the police official said.

Police are still investigating the extent of the scam.

"We think that there could be more people involved in the operation and possibly someone above who was organizing," the official said, noting that it was rare to see South American victims in a sex trafficking case in South Korea.

Over the past few years, South Korea's $4.7 billion entertainment industry has won over an international audience eager for the country's films, music and beauty products.

There's no shortage of young singers and dancers hoping to break into the highly competitive entertainment industry, and K-pop idols often undergo rigorous training from a young age.

The promise of success in this expanding industry has attracted talent from other countries, including Blackpink star Lisa, who comes from Thailand.