Keith Raniere, the co-founder of the NXIVM corporation, a secretive Colonie-based organization that an expert has called an "extreme cult," was arrested in Mexico this week by the FBI based on a federal criminal complaint filed in the Eastern District of New York.

The complaint, filed recently in connection with an ongoing federal grand jury investigation being headed by the U.S. attorney's office in Brooklyn, charges Raniere with multiple counts of sex trafficking and forced labor.

The federal complaint alleges that Raniere, known as "The Vanguard," took part in forming a secretive group within NXIVM in which women said they were coerced into joining a slave-master club and later branded with a design that included the initials of Raniere and Allison Mack, an actress and NXIVM associate who is identified in the complaint as an unnamed co-conspirator.

A warrant for Raniere's arrest was issued more than a month ago. Raniere was taken into custody this week after Mexican immigration officials helped U.S. authorities track him to a luxury, $10,000-a-week villa near Puerto Vallarta, Mexico, where he was staying with several women, federal officials said.

Raniere flew to Mexico last November after U.S. authorities began interviewing "witnesses and victims" associated with NXIVM and the secret club, authorities said.

But finding Raniere had been difficult, they said, because he "began using end-to-end encrypted email and stopped using his phone."

"The defendant was uncooperative when immigration authorities arrived and after he was taken into custody, the women chased the car in which the defendant was being transported in their own car at high speed," prosecutors said in court papers.

Raniere, who co-founded NXIVM more than two decades ago, is being held in federal custody in Texas and is scheduled to make an initial appearance in U.S. District Court in Fort Worth on Tuesday afternoon. Federal prosecutors in Brooklyn have asked a magistrate judge not to set bond and to order Raniere be returned to the Eastern District of New York.

The federal court filings cast Raniere as a manipulative figure who overstated his intelligence and systematically exploited women, including creating a secret slave-master sex club within NXIVM. An affidavit filed by an FBI agent said their investigation found that NXIVM has similarities to a pyramid scheme.

Federal prosecutors, in pressing their case to have Raniere held without bond, said he "has spent his life profiting from his pyramid schemes and has otherwise received financial backing from independently wealthy women."

A person briefed on the case said the federal complaint does not include all of the charges that are being examined by the U.S. attorney's office as part of its ongoing investigation. Raniere faces a mandatory minimum of 15 years in prison if convicted on the sex trafficking charges, according to federal prosecutors.

In a letter to a U.S. magistrate judge on Monday, federal prosecutors said that Raniere "has access to vast resources, (and) poses a significant risk of flight. In addition, his long-standing history of systematically exploiting women through coercive practices for his own financial and sexual benefit demonstrates that, if released, he would pose a danger to the community."

Warning: The document below contains graphic depictions of alleged sexual activity.

Raniere, in statements previously posted on NXIVM's website, had characterized the slave-master group as a consenting, private "sorority" and he said that he and the corporation had no role in it.

But the federal complaint said that emails seized from Raniere's private messaging accounts "support the conclusion that Raniere created" the club, which was known as "Dominus Obsequious Sororium," which means "Master Over the Slave Women."

The women in the group, according to the federal complaint, were lured into the club by other female NXIVM members and required to provide "collateral" in order to join.

"Collateral consisted of material or information that the prospective slave would not want revealed because it would be ruinous to the prospective slave herself and/or someone close to her," states an FBI agent's affidavit filed as part of the complaint. "Collateral provided by prospective slaves included sexually explicit photographs; videos made to look candid in which the prospective slaves told damning stories ( true or untrue) about themselves, close friends and/or family members; and letters making damaging accusations (true or untrue) against friends and family members."

The participants were told the secret club was a "women-only" organization and some were not initially informed that Raniere was the highest member of the organization, the complaint states.

Sarah Edmonson of Vancouver is one of at least 20 women associated with NXIVM who were lured into the club and required them to consent to being branded in their pubic area.

Edmondson said she was never told that the unusual-looking brand was a design that included the initials of Raniere, NXIVM's co-founder, and Mack, a NXIVM associate. In a complaint filed with the New York state Health Department last year, Edmonson identified Mack as having "started" the secret women's group with Raniere.

Edmondson had been associated with NXIVM for 12 years and left the organization in June after she learned the brand that she received contained the initials of Mack and Raniere.

The federal criminal complaint filed against Raniere said the slaves understood that if they left the club, publicly spoke about it, or failed in their obligations, their collateral could be released.

"Some of the masters gave their slaves assignments that either directly or implicitly required them to have sex with Raniere, which they then did," the complaint states. "Other assignments appeared designed to groom slaves sexually for Raniere."

Federal authorities said Raniere does not hold bank accounts in his name, has no driver's license, and for more than a year has used a credit card account associated with a "dead lover" to make purchases.

"In the past year and a half, the defendant and the mother of his child have accessed hundreds of thousands of dollars from a bank account in the same dead lover's name, which contains over $8 million," prosecutors wrote.

Copies of some of the American Express credit card statements associated with that account, which belonged to Pamela Anne Cafritz, who died in November 2016, indicate there were numerous purchases made with that card after her death. The statements, shared with the Times Union last year, indicate the account was used to make purchases from iTunes and Amazon, as well as to make payments to a Saratoga Springs chiropractor.

In their filing that warns a federal magistrate about Raniere's risk of flight, prosecutors noted that Clare W. Bronfman, an heiress of the Seagram Co. business empire who has described herself as the operations director of NXIVM, financially backs Raniere and has paid for private jets — costing up to $65,000 per flight — that have transported him around the world.

"Bronfman also owns a private island in Fiji, which the defendant (Raniere) has visited, and both Bronfman and the defendant have contacts all around the world," prosecutors wrote.

Multiple people who have defected from NXIVM or publicly criticized Raniere have received letters purported to be from Mexican law enforcement officials warning them to "cease and desist" making statements about the organization. Federal prosecutors said that Raniere was behind those letters.

The complaint noted that Raniere was also known to prefer women who are exceptionally thin, and that a number of slaves were "required to adhere to extremely low-calorie diets and to document every food they ate."

The first public disclosures about the branding and the secret club within NXIVM were reported last June by FrankReport.com, an online blog operated by Frank Parlato, who was formerly a publicist for NXIVM. The New York Times later published a story about the secret NXIVM club in October.

But reports about NXIVM's troubling practices are not new. In 2012, the Times Union published an award-winning series — Secrets of NXIVM — that raised questions about NXIVM's inner-workings and also Raniere's questionable dealings with women.

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The Times Union reported in December that the Justice Department's ongoing investigation is also examining NXIVM's business dealings, including its practice of recruiting members from abroad. A federal grand jury empaneled in Brooklyn has been reviewing evidence in the case, according to people who testified before the panel.

Among those who provided testimony are women who claimed they were lured into the secret club that required them to consent to being branded.

NXIVM's supporters have insisted it is a self-help group focused on business improvement. NXIVM officials and associates have repeatedly denied any wrongdoing and dispute any allegation that it is a cult. Recent efforts to reach NXIVM officials for comment have not been successful.

Dating back years, people with connections to NXIVM have filed complaints with various law enforcement agencies, including the New York state Attorney General, the U.S. attorney's office in Albany, the New York State Police, the U.S. Immigrations and Customs Enforcement Agency, the Internal Revenue Service and the FBI.

But law enforcement sources said the federal probe in Brooklyn was the first significant investigation involving either the organization or its leader, Raniere.

The federal court records unsealed Monday also disclose information about Raniere that raise questions about some of his assertions through the years, including boasting that he has one of the highest IQs in the world.

"Nxivm students are also taught that the defendant is the smartest and most ethical man in the world," federal prosecutors wrote in their letter seeking detention for Raniere. "He frequently cited having earned three degrees from Rensselaer Polytechnic Institute, but a review of his transcript shows that he graduated with a 2.26 GPA, having failed or barely passed many of the upper-level math and science classes he bragged about taking."

On Sunday, the Times Union reported that New York Attorney General Eric Schneiderman's office is investigating a nonprofit foundation associated with NXIVM that allegedly sponsored brain-activity and other human behavioral studies without any apparent oversight, according to court records.

The nonprofit Ethical Science Foundation was formed in 2007 by Bronfman, who owns a horse farm in Delanson and is listed in public records as the trustee and donor of the foundation.

A state Supreme Court justice recently signed an order directing Bronfman and Dr. Brandon B. Porter, who is involved with NXIVM and conducted the human studies, to turn over all documentation associated with the research, including any written communications, videos, conclusions, consent forms and the names and addresses of "individuals associated with Ethical Science Foundation who participated in any manner with the studies."