An actress who starred in the US television series Smallville has been arrested on charges of sex trafficking.
Allison Mack, 35, was accused of recruiting sex slaves for a self-help guru and helping to brand them with his initials.
Mack featured in Smallville, a show about Clark Kent’s childhood in Kansas before he becomes known as Superman, which ran from 2001 to 2011. The actress played Chloe Sullivan, one of the main character’s best friends
She later became involved with a group called Nxivm – pronounced Nexium – which was promoted as a mentorship organisation for women with courses costing up to $5,000.
The leader of the group was Keith Raniere, 57, who called himself "Vanguard" and presented himself as a guru to the stars.
Prosecutors alleged that Mack was a "slave" of Raniere and recruited other female "slaves" for him, at times holding them down while a symbol bearing his initials was burned into the victims with a cauterising pen.
At a brief hearing in a New York court Mack pleaded not guilty to sex trafficking.
Richard Donoghue, the prosecutor, said in a statement that Raniere had, over two decades, established Nxivm in Albany, New York and it had centres in the US, Mexico, Canada and South America.
He said it was a pyramid scheme in which participants were encouraged to recruit others in order to rise in the system.
Within Nxivm there was a secret society called "DOS" which was an acronym for a Latin phrase, loosely translating as "’Lord/Master of the Obedient Female Companions". It was also known as "The Vow".
Those who were part of The Vow were referred to as "’slaves" and "masters".
Mr Donoghue said: "Raniere stood alone at the top of the pyramid. Other than Raniere, all members were women. Mack is one of the women in the first level of the pyramid.
"The victims were exploited, both sexually and for their labour, to the defendants’ benefit."
He said up to 50 women were recruited and forced to have sex with Raniere.
They were placed on extreme diets and subjected to "readiness drills" in the middle of the night, which meant they were "seriously sleep-deprived:.
On joining the secret society they had to provide "collateral" like naked photographs which could be sued used against them if they left, prosecutors said.
Assistant US Attorney Moira Kim told the New York court: “Ms Mack was one of the top members of a highly organised scheme which was designed to provide sex to Raniere.
"Under the guise of female empowerment she starved women until they fit her co-defendant’s sexual ideal, and she targeted vulnerable women."
Mack was due to appear in court again on Monday in another attempt to get bail.
Nxivm has denied being a cult, and described itself on its website as being guided by "humanitarian principles that seek to empower people and answer important questions about what it means to be human".
It attracted some high profile followers and during Mack’s court hearing it was revealed she recently married a former Battlestar Galactica actress, the New York Post reported.
Sean Buckley, a lawyer for Mack, said: "The allegations contained in the indictment are only that, allegations."
Raniere was arrested last month in Mexico and charged with sex trafficking. He is being held without bail.
Raniere, on the group’s website, has denied "abusing, coercing or harming" anyone.
Marc Agnifilo, a lawyer for Raniere, has said he is "confident" the allegations will be disproved.