Keith Raniere, a former self-help guru, on Tuesday went on trial in the US on charges of running a secretive New York sex cult that recruited female "slaves".
The 58-year-old American allegedly then starved and branded the women with his initials as well as blackmailing them into having sex with him.
Raniere was the leader of an upstate New York group called Nxivm — previously likened to a cult — which federal prosecutors claim he used as a front for crimes including sex trafficking, child pornography and sexual exploitation of a minor.
Testimony from women who claim that they were forced to have sex with Raniere is set to feature in the trial.
Prosecutors have not said who will take the stand, but former "Smallville" actress Allison Mack already pleaded guilty to playing a supporting role in the group in early April.
Heiress of Seagram liquor — a Canadian multinational conglomerate — Clare Bronfman also pleaded guilty to harbouring an undocumented immigrant and enabling credit card fraud as part of the alleged sex cult.
She provided key financial support for Nxivm for which she agreed to forfeit $6 million (around €5.37 million).
Mack, Bronfman and three other female co-defendants' guilty pleas for various charges in March and April leave Raniere as the sole person to face trial.
Jurors have been warned to expect disturbing testimony and evidence, including explicit photographs of a 15-year-old girl seized from the ex-guru's computer, during a trial that lasts six weeks.
The scheme was exposed in the New York Times newspaper in 2017 and Raniere was arrested while on the run in Mexico in March 2018.
Nxivm (pronounced "Nexium") was created under another name in 1998 and was based in Albany, New York.
At one point it operated numerous centres across the United States, Canada, Central America and Mexico.
Prosecutors say that in 2015 Raniere formed a sub-group called DOS, an acronym for a Latin phrase that roughly translates to “master of the obedient female companions”, through which he recruited "slaves".
Slaves were expected to obey "masters" and recruit other people to the group, which functioned in pyramid-like structure with Raniere situated at the top, they added.
He has pleaded not guilty to all charges.
One of his lawyers said his client’s sexual encounters with women in the organization were consensual and denied the child pornography and exploitation charges.
If convicted Raniere faces up to life in prison.