Actress Allison Mack, known for her work on the superhero TV series “Smallville,” was arrested Friday and accused of recruiting women into a purported self-help organization, Nxivm, in which they were required to work and have sex with the group’s leader, Keith Raniere, prosecutors said.

U.S. attorney Richard P. Donoghue said in a statement Friday that Mack recruited women for Raniere, and that the women were “exploited, both sexually and for their labor.” He said Mack, who was arrested in Brooklyn, New York, is accused of “directly or implicitly” requiring women “to engage in sexual activity with Raniere. In exchange for this, Mack received financial and other benefits from Raniere.”

Raniere was arrested in Mexico in March. He traveled there after The New York Times published a report in October about the group branding women. Mack’s involvement with the group has long been a subject of speculation: She can be seen in a series of conversations posted to YouTube last year, smilingly interviewing Raniere about his teachings.

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His charges in March involve sex trafficking and conspiring to force labor. According to Donoghue, Raniere, known within the group as “The Vanguard,” created “a secret society of women whom he had sex with and branded with his initials, coercing them with the threat of releasing their highly personal information and taking their assets.”

A complaint filed against Raniere alleges that he established “a series of purported self-help workshops” within Nxivm, based in upstate New York.

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Authorities also said Raniere created a secret society within Nxivm in 2015 called “DOS,” which “operated with levels of women ‘slaves’ headed by ‘masters.'”

The Department of Justice alleged in March, following Raniere’s arrest, that some of the DOS slaves became masters who “directly or implicitly required the slaves to have sex with Raniere.” In addition, the DoJ said, many of the DOS slaves were “branded on their pelvic areas using a cauterizing pen with a symbol which, unbeknownst to them, incorporated Raniere’s initials. During the branding ceremonies, slaves were required to be fully naked, and a master would order one slave to film the branding while the others restrained the slave being branded.”

If convicted of the crimes charged, Raniere and Mack each face mandatory minimum sentences of 15 years’ imprisonment, and up to life imprisonment.

An attorney for Raniere did not immediately respond to a request for comment Friday. A publicist for Mack told TheWrap: “I have no comment on the arrest of Allison Mack this afternoon.”