The founder of the secretive self-help group NXIVM has been arrested for sex trafficking and forced labor conspiracy charges.

Keith Raniere, also known as “The Vanguard” to members within the organization, was charged today in Brooklyn federal court with sex trafficking, sex trafficking conspiracy and conspiracy to commit forced labor. The charges arise from Raniere’s alleged role as the leader of a secret society within NXIVM. According to the U.S. States Attorney's Office, Raniere was deported by Mexican authorities after he was found Sunday outside Puerto Vallarta, Mexico in a luxury villa.

“As alleged in the complaint, Keith Raniere created a secret society of women whom he had sex with and branded with his initials, coercing them with the threat of releasing their highly personal information and taking their assets,” U.S. Attorney for the Eastern District of New York Richard Donoghue said in a statement today. Raniere’s initial appearance is scheduled for Tuesday afternoon at the federal courthouse in Fort Worth, Texas. The U.S. Attorney sent a letter to Judge Steven Gold, who is expected to preside over the hearing, asking that Raniere be denied bail.

NXIVM is a secretive self-help organization based in Albany, New York, that was founded by Raniere and Nancy Salzman. It touts itself as a “professional coaching company” and its website says it offers “Executive Success Programs,” or “ESP,” in New York, California, Canada, Mexico and elsewhere.

ABC News "20/20" did an extensive report on the group last year, including interviews with several former members, including Sarah Edmondson, who said she was a member of the group for over a decade.

Edmondson told ABC News and said in a complaint to the New York State Department of Health that after attending NXIVM seminars for more than a decade, she was approached about an opportunity to join a secret sorority. Then, one night she said she and five other women were summoned to a house in Albany, where they thought they were going to get a tattoo, but once there, found out she and the other women were going to be branded.

“It was a horror movie,” she told "20/20." “It was the most inhumane, horrific way to treat anybody. But the most horrific thing is that it’s women doing it to women.”

Edmondson said each of the women would lie down naked and then was branded with a cauterizing device, without any anesthesia. When it was her turn, Edmondson said the pain felt “worse than childbirth.”

As outlined in the Department of Justice press release, the complaint, which was unsealed today, alleges that “in 2015, Raniere created a secret society within Nxivm called ‘DOS,’ which loosely translated to ‘Lord/Master of the Obedient Female Companions,’ or ‘The Vow.’ DOS operated with levels of women ‘slaves’ headed by ‘masters.’ Slaves were expected to recruit slaves of their own (thus becoming masters themselves), who in turn owed service not only to their own masters but also to masters above them in the DOS pyramid. Raniere stood alone at the top of the pyramid. Other than the (sic) Raniere, all members of DOS were women.”

In Donoghue’s letter to the judge requesting that bail be denied, he asserts that Raniere has had more than fifty DOS slaves under him, many of whom were recruited from within NXIVM’s ranks.

“As alleged, Keith Raniere displayed a disgusting abuse of power in his efforts to denigrate and manipulate women he considered his sex slaves,” FBI’s New York Field Office Assistant Director-in-Charge William F. Sweeney, Jr. said in a statement. “He allegedly participated in horrifying acts of branding and burning them, with the cooperation of other women operating within this unorthodox pyramid scheme. These serious crimes against humanity are not only shocking, but disconcerting to say the least, and we are putting an end to this torture today.”

After reports started surfacing about DOS, a letter was posted on the NXIVM website, in which Raniere said, "The picture being painted in the media is not how I know our community and friends to be, nor how I experience it myself. However, as an organization and as individuals, we felt it was imperative that we hire experts to ensure there is no merit to the allegations."

"Additionally, I feel it is important to clarify the sorority is not part of NXIVM and that I am not associated with the group," the statement continued. "I firmly support one’s right to freedom of expression, so what the sorority or any other social group chooses to do is not our business so long as there is no abuse. Our experts, a forensic psychiatrist of international repute, psychologists and ex-law enforcement, say members of the sorority are thriving, healthy, happy, better off, and haven’t been coerced. Furthermore, the sorority is proud of what they created and want to share their story. I am confident they will be addressing you very soon."