Federal prosecutors on Monday charged Keith Raniere, the co-founder of self-described “self-help” group Nxivm, with sex-trafficking crimes. Raniere was arrested in Mexico. The secretive group allegedly recruited and brainwashed women into sex slavery. Raniere, who was known as the “vanguard” or master, had his initials branded in the women’s pelvic areas, prosecutors said. He was found in Puerta Vallarta, where he fled after The New York Times first exposed the group. “As alleged in the complaint, Keith Raniere 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,” said Richard P. Donoghue, U.S. Attorney for the Eastern District of New York.