Keith Raniere has been accused of facilitating sex trafficking and child pornography.

The founder of an alleged New York sex cult held meetings in which female "slaves" gathered naked on the floor around him while he sat in a chair and lectured them on philosophy, one of the women testified at his criminal trial on Friday.

The former "slave," Lauren Salzman, told jurors in federal court in Brooklyn that the group's leader, Keith Raniere, would preside over the meetings fully clothed. When he was unable to attend the meetings in person, the women would take a naked photo and text it to him - making sure he could see where he had branded them with his initials, Salzman said.

"We were to look uniform and happy," said Salzman, 42.

Raniere, 58, faces charges including sex trafficking and child pornography for allegedly using his self-help group, Nxivm, to hide a secretive sorority known as DOS in which young women were forced to have sex with him, follow dangerously restrictive diets and obey his every command.

If convicted of the most serious charges, Raniere faces life in prison. His lawyer has argued at trial that the women became members of Nxivm voluntarily and were never coerced into doing anything against their will.

Witnesses at the trial, which began last week, have detailed how Nxivm's teachers portrayed Raniere as "some kind of god" who would unlock a more fulfilling life for his followers.

Salzman, whose mother, Nancy, served as Nxivm's president, was a "first-line slave" within DOS, which meant she answered directly to Raniere and had slaves of her own beneath her, she said.

Other first-line slaves included former "Smallville" actress Allison Mack, who like Salzman previously pleaded guilty to her part in Raniere's crimes. Nancy Salzman has also pleaded guilty.

Earlier this week, a 12-year Nxivm veteran, Mark Vicente, testified he grew concerned that Mack and other young women in the group had become too thin after following a severely restrictive diet at Raniere's order.

When Vicente told Raniere that Mack seemed "broken," Raniere responded, "I'm trying to break her," Vicente testified.

On Friday, Lauren Salzman described her own culpability, telling jurors how she, Raniere and others held a woman captive inside a room for two years under the threat of sending her back to her native Mexico.

She also acknowledged recruiting slaves for DOS and extorting them by demanding compromising material, like nude photos, that could be used as blackmail if they refused orders.

Salzman first met Raniere through her mother in 1998, when she was 21, and soon began a sexual relationship with him that lasted for years.

"He was my mentor and teacher," she said. "He was my most important person."