Mexixo - The founder of US-based self-help groups faces the possibility of life in prison if convicted on charges of sex trafficking, according to authorities who say he ran a secret society that enslaved women and branded them with his initials.

Keith Raniere, who was arrested in Mexico, appeared in court in Fort Worth, Texas on Tuesday for a formal reading of charges against him.

US authorities say Raniere created a secret society of women, forcing them to have sex and branding them with his initials.

He coerced them by threatening to release personal information and taking their assets, according to a complaint filed in New York federal court.

"As alleged, Keith Raniere displayed a disgusting abuse of power in his efforts to denigrate and manipulate women he considered his sex slaves," William Sweeney, FBI assistant director in charge, said in a statement.

"He allegedly participated in horrifying acts of branding and burning them," he said. "We are putting an end to this torture today."

Raniere, 57, has run a network of self-help groups based in Albany, New York called Nxivm over the past 20 years, according to the court complaint.

A secret society within Nxivm consisted of female "slaves" required to have sex with Raniere, according to women cited in the complaint.

The women, who numbered as many as 50, were branded with symbols including Raniere's initials and forced to adhere to strict diet to stay thin, said the complaint.

Upon joining, they were required to provide information about family and friends, nude photographs and rights to their assets - so-called collateral used to threaten them if they left, the complaint said.

The women were taught that the society would empower and strengthen them, the complaint said.

Raniere, arrested on Sunday at a luxury villa near the Mexican resort of Puerto Vallarta, was deported to Texas for his court appearance.

He faces charges of sex trafficking, sex trafficking conspiracy and forced labor conspiracy.

If convicted, Raniere faces the possibility of 15 years to life in prison.

He will be moved to New York for further hearings.

Raniere has the backing of a wealthy heiress and access to an $8 million bank account of a deceased lover, court documents said.

Authorities said he fled to Mexico after investigators began interviewing witnesses in November.

On its website, Nxivm calls itself "a community guided by humanitarian principles that seek to empower people and answer important questions about what it means to be human."

In a letter on the site, Raniere said he was "deeply saddened" and denied "abusing, coercing or harming" anyone. 

Thomson Reuters Foundation