An Argentina-based yoga group sexually exploited vulnerable women it called “geishas” to get money and influence from wealthy and powerful men around the world, including opera star Placido Domingo, who knew the organization’s leaders for more than two decades, according to interviews with former members and local authorities.

A sprawling investigation into the sect-like Buenos Aires Yoga School, which operated for over 30 years in Argentina’s capital, has uncovered what authorities are calling a criminal organization involved in sex trafficking, money laundering, involuntary servitude, illegal practice of medicine and other crimes. Nineteen members have been arrested in the investigation that reaches into the U.S., where six more suspects are sought.

Despite its name, the school did not offer yoga classes. Leaders are accused of preying on people to join its ranks with promises of eternal happiness and then exploiting them sexually and financially, according to charging documents.

Former members of the school and officials investigating the case told The Associated Press that the group forced female members to work as “geishas” who were assigned to make guests feel welcome at the school, with sex part of the expectations. Influential or wealthy men were matched up with members of the “Geishado VIP,” one of many groups of women that were forced to have sexual encounters in exchange for money and influence that benefited sect leaders, according to the charging documents. Some of the women were sent to the United States and Uruguay to have sex with men, a practice that amounted to slavery, authorities said.

Former member Pablo Salum said his mother and sister were among the women exploited in Argentina, and described orgies and sexual abuse of children.