"Smallville" actress Allison Mack was arrested Friday, accused of having a role in an upstate NY sex slave cult.
Mack pleaded not guilty to the charges against her when arraigned on Friday afternoon before United States Magistrate Judge Cheryl Pollak. He was previously arrested on a complaint and ordered detained.
Raniere, the co-founder of the self-help organization and alleged cult NXIVM, stands accused of keeping numerous women as slaves and branding his initials into their skin.
Law enforcement officials told NBC New York that Mack was taken into custody, although no further details are yet available.
"As alleged in the indictment, Allison Mack recruited women to join what was purported to be a female mentorship group that was, in fact, created and led by Keith Raniere", United States Attorney Richard P. Donoghue said in the statement. Raniere, who started the group, has been charged with sex trafficking by federal prosecutors.
An indictment was also unsealed on Friday in federal court. The filings allege that DOS had levels of women "slaves" headed by "masters" in a pyramid scheme, with Raniere at the top and Mack immediately below Raniere.
Mack allegedly collected "collateral" from her slaves - like sexually explicit photographs and letters containing damaging accusations against their friends and family - which prosecutors claimed she could use to scare off witnesses. The complaint also stated the actress was Raniere's slave and had sex with him.
Raniere and Nxivm have been the subject of criticism for years, dating back to at least 2012 when the Times Union of Albany published a series of articles examining the organization and allegations that it was like a cult.
Mack is reportedly Raniere's second-in-command and was caught on video objecting to his arrest in Mexico last month. Raniere was the sole male in DOS and the leader.
Following Raniere's arrest, Mack's longtime co-star Kristin Kreuk felt compelled to issue a statement clarifying that she had nothing to do with the organization, despite rumors to the contrary. Kreuk says she left NXIVM years ago and commended the women who exposed DOS.
Mack and Raniere face a minimum of 15 years in prison if convicted.