Actor Allison Mack exits with her lawyer following a hearing on charges of sex trafficking in relation to the Albany-based organization Nxivm. Picture: Reuters

NXIVM called itself a humanitarian community. Experts called it a cult.

Shortly after the arrest of US actress Allison Mack, the lid was lifted on Nxivm, a purported executive coaching organisation.

Mack, best known for her role as Clark Kent's friend in superhero television series 'Smallville,' was one of six defendants who were arrested a year ago on sex trafficking charges for recruiting women to join Nxivm. It reportedly forced them to have intercourse with 58-year-old leader Keith Raniere.

Before being accepted as "slaves," women had to provide compromising photos and other personal effects, which the organisation threatened to make public if they tried to leave, AFP reported.

They also had their skin branded with Raniere's initials as other members held them still and filmed.

'Uncover: Escaping NXIVM' is an investigative series from CBC Podcasts and CBC News about the organisation, its leader Keith Raniere and one woman's journey to get out.