Smallville star Allison Mack has started her three-year prison sentence for recruiting women into Keith Ranieres Nxivm sex cult.

The cult, which disguised itself as a self-help organization, was responsible for sexually abusing multiple women.

The actress was sentenced to three years in prison and charged a $20,000 fine for her involvement in the cult. Raniere was sentenced to 120 years in prison for racketeering, racketeering conspiracy, sex trafficking, attempted sex trafficking, sex trafficking conspiracy, forced labor conspiracy and wire fraud conspiracy.

Prosecutors asked for lenient sentencing for Mack because she cooperated with investigators, and provided a recording of a ceremony where women were branded with Raniere’s initials.

“Although Mack could have provided even more substantial assistance had she made the decision to cooperate earlier, Mack provided significant, detailed and highly corroborated information which assisted the government in its prosecution,” wrote acting United States Attorney Jacquelyn M. Kasulis.

Mack apologized for her involvement in the cult. “I believed, whole-heartedly, that [Raniere’s] mentorship was leading me to a better, more enlightened version of myself” and continued to say that “this was the biggest mistake and regret of my life.”

In a letter to the court, she addressed the victims that she had a role in recruiting, and apologized for the pain she caused them.

“I am sorry to those of you that I brought into Nxivm,” she wrote. “I am sorry I ever exposed you to the nefarious and emotionally abusive schemes of a twisted man. I am sorry that I encouraged you to use your resources to participate in something that was ultimately so ugly.”

The star arrived at California’s Federal Correctional Institution in Dublin on Monday, two weeks before her scheduled start date of Sept. 29.

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