Members of a close-knit family from Mexico ventured to upstate New York in the early 2000s to seek enlightenment from self-help guru Keith Raniere. They got something much darker.

Prosecutors say Raniere sexually exploited three sisters in the family and confined one of them for two years for defying his arbitrary edicts.

"It was all lies," the captive sister said this week at Raniere's ongoing federal sex-trafficking trial in Brooklyn. "I was set up."

The family's tale is a central subplot to a trial in which Raniere has been accused of being a sadistic con man who abused women under the guise of giving them a path to personal growth. His lawyers say their client had no criminal intent and that all his encounters with female followers who joined a group called NXIVM were consensual.

Some of the most sensational evidence against Raniere relates to accusations he required "sex slaves " who joined a secret society within NXIVM be branded with his initials.

But the harrowing testimony about his treatment of the sisters from the Mexican family before any branding began captivated the courtroom this week as the man once addressed as "Vanguard" by his devotees looked on from the defense table, often taking notes but showing no emotion.

One of the sisters — whose full names have been withheld by prosecutors to protect their privacy — took the witness stand to offer an often sexually graphic narrative about her family's experience with Raniere.

It began when her parents, after taking NXIVM courses, fell under the spell of someone the organization billed as "the smartest man in the world," she said.

The witness, now 33, gave up a formal education to go to the group's Albany-area headquarters to do an internship in 2002 when she was 16, she said. Meeting Raniere was like meeting a "rock star," she said, but the experience quickly went bad when she found herself doing menial work with no pay. She was also accused of trumped-up "ethical breaches."

Raniere, who was in his 40s at the time, offered to tutor her before he hinted he should take her virginity when she reached 18, she said.

She soon became a member of an "inner circle" of worshippers who attended to Raniere's every need, sexual and otherwise, she said. He said the sex was necessary to "help them grow," she said.

Her older sister eventually was sent to join NXIVM and also became one of Raniere's many sex partners, she said. All had to abide by a strict set of rules: No sex with other men. No birth control. No gaining weight. No telling anyone.

At one point, Raniere tried to lure her and her older sister into a threesome, she said. But before it could get too far, she said, "I was crying. She was crying. I felt dirty."

The situation only got worse when a younger sister, then only 15, was brought into the NXIVM world, she said. The witness said that when Raniere told her he was having sex with the teen sister, she initially felt "jealous" that "he made me wait until my 18th birthday."

She watched her younger sister fall into a depression so deep that she started cutting herself. Looking back, "I deeply regret that I didn't get her out of there," she said.

As tensions grew with Raniere, he stopped talking to the middle sister and assigned one of his closest followers to order into a bedroom with only a mattress and a pen and paper to write apologies to Raniere.

The follower, Lauren Salzman , testified as a cooperating government witness that what was supposed to be a brief punishment for the sister stretched out to nearly two years under orders by Raniere and with the approval of her parents. When she finally demanded to be let go in 2010, she was sent back to Mexico.

The sister was to resume her story with more testimony at the trial on Tuesday. Salzman suggested the ending isn't happy.

The family members "were close when they came to us, and those relationships were incredibly severed," Salzman said. "And I don't know how you can ever recover from that. I think it's terrible."