Mr. Ray “exploited that vulnerable time in these victims’ lives through a course of conduct that shocks the conscience,” Mr. Berman said.

Mr. Ray’s extortion scheme relied on false confessions that he extracted from his victims, using tactics like sleep deprivation, psychological and sexual humiliation, verbal abuse, physical violence and threats of legal action, the indictment charged. He got them to falsely confess to damaging property and in some cases to trying to poison him, then used those confessions as leverage, the indictment said.

Mr. Ray was also accused of laundering about $1 million he obtained from his victims, the indictment said. He was arrested on Tuesday morning at his home in Piscataway, N.J., and was ordered jailed overnight after a brief hearing in Federal District Court. Mr. Ray was escorted into the courtroom smiling, dressed in a flannel shirt, cargo pants and work boots with his legs shackled.

The investigation that led to the charges against Mr. Ray was prompted by an article in New York magazine in April titled “The Stolen Kids of Sarah Lawrence,” Mr. Berman said at the news conference.

The startling accusations are all the more remarkable for the environment in which prosecutors say they first played out — the verdant Sarah Lawrence campus, where red brick buildings frame wide lawns and a wisteria arbor dominates the grounds.

Equally remarkable is Mr. Ray’s own strange history, a life where he seemed to seesaw between mob figures, on the one hand, and top law enforcement and military officials, on the other; he even has made claims, largely credited, that he worked for a United States intelligence agency in Kosovo.

He was an F.B.I. informant in the late 1990s, dishing dirt about a Gambino crime family soldier, but his efforts to cooperate with the bureau failed, and he was later charged with more than a dozen other men in a federal racketeering and stock fraud case in Brooklyn.