Mack was arrested in New York on Friday, April 20 and indicted on a string of counts amid allegations suggesting she was second-in-command of the NXIVM collective and a sub-group called Dominus Obsequious Sororium (DOS), where women were forced to perform sex acts for their male masters.
She is said to have worked for leader Keith Raniere, convincing women to join what they called a female empowerment group from February 2016 to June 2017.
Mack, who has pleaded not guilty to the charges, was remanded in custody following her indictment, as her lawyers went to work on securing a deal with federal prosecutors.
Raniere, who was arrested in Mexico last month and extradited to the U.S. to face charges of sex trafficking and forced labour counts, was also indicted on Friday. Both face mandatory minimum sentences of 15 years to life in prison if convicted.