A woman implicated in the sex-trafficking case against an upstate New York self-help group that's been compared to a cult has quietly pleaded guilty to conspiracy charges. Lauren Salzman, the daughter of NXIVM co-founder Nancy Salzman, pleaded guilty Monday to racketeering and racketeering conspiracy at a hearing that wasn't on the court calendar.

Afterward, a judge agreed to seal a transcript until parts of it could be blacked out. The U.S. attorney's office declined to comment on Friday about how the plea was handled.

In this Jan. 28, 2019 file photo, Lauren Salzman leaves Brooklyn federal court in New York. AP Photo/Seth Wenig, File

Salzman, 42, was one of the four co-defendants of Keith Raniere, the leader of NXIVM, pronounced nehk-see-uhm. She entered her plea two weeks after her mother, Nancy Salzman, 64, pleaded guilty to a charge of racketeering criminal conspiracy. They are the first two to plead guilty in the case.

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Prosecutors this month added charges accusing Raniere of exploiting teenage girls. That sparked speculation his co-defendants might agree to cooperate against him.

Raniere, 58, was charged March 13, with exploiting a child and possessing child pornography. He denied the allegations. Raniere had previously pleaded not guilty to charges accusing him of operating a secret society within his NXIVM group that forced women "slaves" to have unwanted sex with him and branded them with his initials.

Raniere has called NXIVM a self-help group, but investigators allege it was a multi-level marketing scheme used as a ruse to enslave and traffic women for sex.

Raniere has been jailed without bail since being brought to the U.S. in 2018 following his arrest in Mexico. Opening statements in the criminal trial are scheduled to take place April 29 in Brooklyn federal court.

Assistant U.S. Attorney Moira Penza told a judge on March 18 that the government is in "active plea negotiations" with three defendants. Included among the three remaining defendants contesting their charges is Allison Mack, best known for playing a teenage friend of Superman on the "Smallville" TV series.

Additionally, Seagram liquor fortune heiress Clare Bronfman was expected to seek a separate trial on charges she bankrolled the Albany-based group, which has also been called a pyramid scheme.