As the trial of the group’s founder, Keith Raniere, begins, experts say people attracted to change are vulnerable to manipulative ‘cultish group behavior’

The federal courthouse in Brooklyn provided a bland judicial setting for some startling testimony this week, as former members of Nxivm, a self-improvement and wellness group that was allegedly a sex cult, described how devotees were manipulated to the point of enslavement to the group’s founder, Keith Raniere.

A case which on the surface contained the compelling components of wellness, self-improvement, celebrity and wealth was quickly reduced to accusations of base criminality.

Opening arguments are set for Tuesday in Brooklyn federal court as prosecutors have been tight-lipped about who will testify

It was called “collateral” – nude photos and other embarrassing material that female members of an upstate New York self-improvement group turned over to their “masters” to guarantee obedience, silence and sexual fealty to the organization’s spiritual leader, Keith Raniere.

Now some former members of the group, called Nxivm (pronounced nexium) are poised to break their vow of silence by testifying against Raniere, who has been compared to a cult leader. Opening arguments are set for Tuesday at a federal court in Brooklyn.

• Bronfman, 40, admits credit card fraud and immigration charges
• Plea means Nxivm founder Keith Raniere will stand trial alone

The Seagram liquor heiress Clare Bronfman pleaded guilty on Friday to harboring an undocumented immigrant and enabling credit card fraud as part of an alleged sex cult based in upstate New York, where women have reported they were branded with the initials of the founder.

Bronfman, 40, entered her plea to the two criminal counts before Judge Nicholas Garaufis in federal court in Brooklyn, New York.