Raniere's conviction follows the April guilty plea by his top lieutenant in the group, former Smallville actress Allison Mack

Nxivm founder Keith Raniere, the leader of the controversial New York-based self-help group, was found guilty Wednesday of federal sex trafficking and racketeering charges, according to John Marzulli, a spokesman for the prosecutor’s office.

Raniere had pleaded not guilty on all seven charges he faced. His conviction follows the April guilty plea by his top lieutenant in the group, former Smallville actress Allison Mack, to racketeering conspiracy and racketeering charges. Mack will be sentenced in September.

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Prosecutors described Nxivm as a sexual pyramid scheme involving sex slaves, with Raniere at the top. The group has long marketed itself as a group that empowers people and helps them manage emotional trauma, but prosecutors said it has a darker side built on coercion and manipulation.

CNN reports that US attorney Richard Donoghue said that “Raniere, who portrayed himself as a savant and a genius, was in fact a massive manipulator, a con man, and the crime boss of a cult-like organization involved in sex trafficking, child pornography, extortion, compelled abortions, branding, degradation and humiliation.”

Investigators said Raniere, who was known as “Vanguard” to his followers, occupied the top of a pyramid called DOS, with tiers of female “slaves,” each of whom could become a “master” to slaves beneath them.

One former devotee described Nxivm as a “cult,” and the group has been the subject of scrutiny from both law enforcement and journalists after it came under fire from Dynasty actress Catherine Oxenberg, whose daughter, India, joined in 2011. (India has since left the group.)

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The criminal complaint against Raniere, obtained by PEOPLE, outlines how how authorities believe the women in DOS were forced to turn over “collateral” — identified as potentially-damaging personal information or materials, such as nude photographs, with which they later could be blackmailed.

The women victimized by Mack and Raniere believed their “collateral” would be released if they did not engage in sexual activity with the Nxivm leader, prosecutors have said.

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Authorities said Mack forced DOS slaves, including a woman identified as Jane Doe 1, to have sex with Raniere and that Mack “groomed DOS slaves for sex with Raniere by requiring [them] to adhere to extremely restrictive diets and not remove their pubic hair (in accordance with Raniere’s sexual preferences) and by requiring them to remain celibate and not to masturbate.”

According to arguments prosecutors made in court documents, Mack allegedly demanded that the group’s slaves partake in “readiness” drills requiring them to respond to their masters at any time of night. Mack’s slaves were also allegedly “kept seriously sleep-deprived and emaciated to the point where they stopped menstruating.”

Mack “received financial benefits [in] the form of continued status and participation in DOS, as well as financial opportunities from Raniere,” according to court documents filed by prosecutors.

Raniere was arrested in March 2018 in Mexico.

Prior to his trial, Raniere had sought to have the charges against him dismissed. In a motion, his attorneys described Nxivm as a “wonderful humanitarian organization” that is “dedicated to achieving peace on a global scale.”

The filing adds: “If there was a polar-opposite of an organized crime family, Nxivm would be it.”

The motion further claims that “Nxivm members have sought to end the violence in Mexico, have introduced tools useful to people with difficult conditions, such as Tourette’s syndrome, have pioneered multi-linguistic schools for young children, who would become proficient in multiple languages and later multi-cultural adults, and have developed approaches to help people lead happier, more productive, more enriched lives.”