The founder of the alleged cult NXIVM forced member Allison Mack to store naked photos of women branded with his initials to blackmail them into becoming sex slaves, a former member testified in court Monday.

Lauren Salzman said in Brooklyn federal court that Mack, the Smallville actress, was forced to collect the photographs in a Dropbox folder at the request of her master, NXIVM founder Keith Raniere. Salzman began testifying on Friday and continued this week.

“The photo had to be fully frontal naked,” Salzman said. “Our brands had to show, and we had to look uniform and happy.”

Raniere, 58, is accused of running a secret sex-cult pyramid scheme that branded, assaulted, and enslaved women while publicly promoting NXIVM as a self-improvement group. He is charged with sex trafficking, racketeering conspiracy, child exploitation, and child pornography.

Raniere has pleaded not guilty to all the charges.

Salzman, 42, is among the four NXIVM members—including Mack, and her mother—who were arrested in 2018 with Raniere. After pleading guilty to racketeering charges in March, she is the first co-defendant to testify against Raniere, who is standing the trial alone.

“He was my most important person. I respected him. I looked up to him,” she said. “He was my master.”

Salzman walked jurors through the world of the ultra secretive club DOS, the “secret society” where she said “slaves” would be forced to brand themselves with Raniere’s initials near their crotch with a cautery pen—without anesthesia—and have sex with him.

If any slave displeased Raniere, he would kick or whip them before threatening to release their collateral photos saved under a Dropbox file named “brands,” according to Salzman, who also testified on Monday that Raniere had plans to jail women “in a dungeon” as a form of punishment.

“He said [the jail cell] was for the people most committed to growth. They would get locked in a cage,” she said on Monday.

Salzman testified she met Raniere, whom NXIVM members referred to as “the Vanguard,” through her mother in 1995, and began her sexual relationship with him six years later.

“He was my mentor. My teacher,” Salzman said of their decade-long relationship, which ended before the formation of DOS. “We had a romantic relationship. A physical and sexual relationship.”

Throughout their relationship, Raniere allegedly forbade Salzman to see other people while simultaneously forcing her to partake in threesomes with other alleged slaves, including Mack.

“Initially, I participated because I was curious,” she reportedly said.

Salzman added that despite sharing Raniere with Mack, they were close friends and even wrote a letter of support for Mack and fellow DOS member Nicki Clyne’s marriage. Mack is also expected to testify in court as part of her plea agreement.

In 2015, Salzman said Raniere approached her about joining an elite “master-slave program” that would help her “overcome her fears” by submitting herself to his orders, which she accepted immediately. Salzman said she was among seven women who were deemed “first line slaves” to Raniere at the time of the DOS hierarchy and she was responsible for only communicating with other members of her rank and her six slaves.

“I was a slave with Keith as my master,” Salzman said, adding that she was forced to keep the role of Raniere, whom they had to call “grandmaster,” a secret. “And the society demanded a lifetime of obedience to your master.”

The group would meet three times a week in a “sorority house,” and whenever Raniere attended, the women had to strip naked, get on the floor and look up at him, while he delivered lectures on matters ranging from his “vision” for DOS to write a book, to recruitment, to his intent to create a “dungeon” where slaves would “totally surrender” themselves.

“It didn't sound like anything I ever wanted,” Salzman said on Monday, detailing how Raniere would force masters to paddle their slaves if they disobeyed. “These things started to become scary for me. I was concerned about failing.”

In opening statements earlier this month, Raniere’s defense attorney, Marc Agnifilo, called DOS a “women’s organization” Raniere felt women needed. Agnifilo had also argued throughout the trial that the women in DOS engaged in consensual sexual relationships with Raniere.