In New York, a 63-year-old man has been sentenced to 60 years in prison for the sexual and financial exploitation of female students.
Lawrence Ray caused "brutal and lifelong damage" to his victims, the judge said when the sentence was announced, as American media reported on Friday.
He described the man's crimes as "sadism".
Ray was found guilty on 15 charges in April last year, including sex trafficking, extortion, violent assault and money laundering.
The man moved into his daughter's dorm at Sarah Lawrence College, a small college in the New York suburb of Bronxville, in 2010.
He created a kind of cult there by presenting himself as a father figure and winning the trust of his daughter's friends.
In doing so, he took advantage of the fact that his victims suffered from mental problems, as described in Ray's trial in the Manhattan borough of New York.
Accordingly, Ray put the young women under pressure through practices such as sleep deprivation, sexual humiliation, verbal and physical violence.
He thus tricked them into falsely admitting that they had caused him material harm.
Victims then paid for it by drawing on their parents' savings, borrowing money from friends, or selling real estate.
Also, according to the case files, the victims performed "extensive physical labor" for Ray on the property of one of his relatives -- without being paid and sometimes in the middle of the night.
Ray also reportedly collected sexually explicit photos of one of the women and forced her into prostitution - which is said to have netted him millions of dollars in revenue alone.
According to the judicial information, Ray operated his exploitation of female students for more than a decade.
He laundered his earnings via an Internet company and thus avoided paying taxes.