NEW YORK — A federal prosecutor says there could be more criminal charges brought against the leader of a purported self-help group who's accused of forcing women into having unwanted sex.

Assistant U.S. Attorney Moira Penza also told a Brooklyn judge at a hearing on Thursday that it's possible more people could be charged in the investigation of Albany, New York-based NXIVM (NEHK'-see-uhm) and its founder, Keith Raniere.

Raniere and five other people are facing sex-trafficking and other charges. They include television actress Alison Mack and Clare Bronfman, heiress to the Seagram's liquor fortune.

Authorities say Bronfman and Mack helped Raniere form a secret society of sex slaves who were branded with his initials.

Mack is best known for her role in the CW network's "Smallville."

All the defendants have denied the allegations.