Several women members of an alleged New York sex cult, including “Smallville” actress Allison Mack, became dangerously thin after following near-starvation diets at the direction of the group’s leader, a 12-year veteran of the group testified on Monday.

The long-time member, filmmaker Mark Vicente, is a key prosecution witness at the criminal trial of Keith Raniere, whom authorities have accused of forcing female “slaves” within his NXIVM organization to have sex with him, lose weight and get branded with his initials.

Vicente, who left NXIVM in 2017, said he told Raniere that Mack seemed “broken,” and Raniere responded, “I’m trying to break her.”

Story continues below advertisement

Mack, who starred in the television series “Smallville” for a decade, was one of five co-defendants, including Seagram liquor heiress Clare Bronfman, who previously pleaded guilty to NXIVM-related crimes.

Vicente told jurors in U.S. District Court in Brooklyn that the women would push their diets even further, limiting themselves to a few hundred calories a day, as penance if they slipped up.

“There seemed to be kind of a club of young women gathering around Allison Mack, and they just didn’t look healthy,” he said.

Vicente previously told jurors that Raniere’s recruits came to view him as “some kind of god,” thanks to a sales pitch that portrayed him as a genius of unparalleled insight.

Story continues below advertisement

Prosecutors say Raniere traded on that status to force female “slaves” who had joined a secretive sorority within NXIVM to follow his every command. The slaves were required to submit “collateral,” such as nude photos, that Raniere then used as blackmail to coerce their compliance, according to authorities.

Raniere’s lawyer has argued at trial that the women joined voluntarily and were never forced to do anything against their will. Raniere faces life in prison if convicted.

Raniere and his closest acolytes exercised strict discipline and control over his followers, Vicente said, forcing those who questioned his leadership to undergo training and excommunicating those who went against the group.

“Many of us became very, very careful of the words we used,” he said.

Story continues below advertisement

Vicente, who became the group’s unofficial videographer, told jurors last week he was asked by the group’s president, Nancy Salzman, to make videos showing Raniere in a positive light.

“I really would love it if Keith Raniere does not die a criminal in the eyes of the world,” Salzman told Vicente, according to his testimony. Salzman has pleaded not guilty.

NXIVM, which started under another name in 1998 and is pronounced “Nexium,” was based in Albany, New York, and operated self-improvement centres across North and Central America.