[What you need to know to start the day: Get New York Today in your inbox.]
The cache of documents surfaced in 2018 when the F.B.I. searched the home of a senior member of the cultlike group Nxivm.
Photographs from the search showed agents had found a clear plastic box with a red lid in the basement of a home belonging to Nancy Salzman, Nxivm’s co-founder, who was known as “Prefect.”
Inside, agents said, were folders of financial reports labeled with names of journalists, judges, cult experts and others, including Senator Chuck Schumer; the then state attorney general, Eliot Spitzer; and the State Senate majority leader, Joseph L. Bruno.
Most, if not all, of the financial material was inaccurate, an F.B.I. agent, Michael Weniger, said. But Nxivm members appeared to be making a genuine effort to gather information on the targets.
“The vast majority of the individuals that had folders inside the box were individuals that had some type of criticism of Nxivm and or the defendant,” he testified on Thursday in the racketeering and sex trafficking case of the group’s leader, Keith Raniere.
Mr. Weniger finished testifying on Friday, closing the prosecution’s case six weeks after it began on May 7. Afterward, the defense declined to present witnesses, and in the only instance during the trial in which he has spoken publicly, Mr. Raniere confirmed to the judge in a soft voice that he would not be taking the stand.
Summations are scheduled for Monday.
Over the course of the trial in Federal District Court in Brooklyn, six former Nxivm members offered wrenching and sometimes lurid accounts of manipulation and sexual abuse.
But Mr. Weniger appeared to serve as an expert of sorts, someone who could draw from broad knowledge of Nxivm and introduce documents involving members who were not called to the stand.
Mr. Raniere, 58, co-founded Nxivm (pronounced nex-ee-um) in the 1990s as a self-help organization based near Albany. He is now on trial on charges of racketeering conspiracy, identity theft, extortion, forced labor, money laundering, wire fraud and sex trafficking.
Although he presented himself as a humanitarian, prosecutors have said Mr. Raniere, known as “Vanguard,” exploited his followers, particularly women. Some were branded with his initials and assigned to have sex with him.
Much of Mr. Weniger’s testimony emphasized the conspiratorial nature of Nxivm and the lengths to which its members would go to monitor those whom they perceived as hostile.
Earlier in the trial, a witness identified only as Daniela said Nxivm tried to obtain personal information and banking records of people on a “list of enemies” who members believed wanted to destroy the group.
She added that she hacked into the computer accounts of several people at the behest of Mr. Raniere and a Nxivm member named Kristin Keeffe.
As part of that effort, Daniela said, she obtained years of emails from the account of the liquor magnate Edgar M. Bronfman Sr., whose daughter, Clare Bronfman, was a senior member of Nxivm.
Among those whose names appeared on folders in Ms. Salzman’s basement were journalists with The Albany Times Union, which had run investigative stories about Nxivm, and four federal judges who had presided over cases involving the group.
Also included was information about the political operative Roger Stone, who Mr. Weniger said had worked for Nxivm; Rick Ross, a cult expert the group had sued; Kristin Snyder, a Nxivm student who was presumed to have died in Alaska; and Mr. Bronfman.
Mr. Weniger said that Ms. Bronfman appeared to have paid an investigations company in Montreal “upward of $400,000.” Email messages introduced as evidence showed that her payments to the company, Canaprobe Group, were for financial reports.
Ms. Keeffe forwarded some of that material to Emiliano Salinas, a Nxivm member whose father, Carlos Salinas de Gortari, had been president of Mexico, the messages also showed. Mr. Salinas then sent it to a man at a private equity fund. And that man sent the information to a private investigator in New York who attempted to verify it, Mr. Weniger said.
In some email exchanges, Mr. Raniere “specifically discusses with Kristin Keeffe the relationship Nxivm had with Canaprobe,” Mr. Weniger testified.
Mr. Weniger acknowledged that it appeared that Canaprobe had given the Nxivm members bogus information and that Ms. Bronfman had eventually sued the company.
One of Mr. Raniere’s lawyers, Marc Agnifilo, suggested to Mr. Weniger that Ms. Keeffe may have been carrying out investigations on her own.
He also portrayed her as paranoid, pointing to an instance in which she was suspicious of a black pickup truck in her neighborhood and an occasion when she theorized that house painters might be conducting undercover surveillance of her home.
But Mr. Weniger testified that Ms. Keeffe was not the only member of Nxivm to exhibit paranoia.
At one point, Mr. Weniger said, Nxivm sent investigators to Key West, Fla., and, apparently, Palm Springs, Calif., to look for Ms. Snyder, the former Nxivm student.
In 2003 Ms. Snyder left an “intensive” Nxivm course in a hotel in Anchorage and wrote a note saying she had been “brainwashed,” the Times Union reported. She was then believed to have intentionally capsized a kayak in the icy waters of Resurrection Bay.
Mr. Raniere believed word of her death was a conspiracy to create “negative publicity,” according to Daniela’s testimony. And Mr. Weniger said there was a belief among Nxivm members that Ms. Snyder “was still alive and that she was moving from place to place.”
The animosity toward Mr. Bronfman, who was the chief executive of the Seagram Company, appeared to be driven by the fact that he was quoted in a story in Forbes magazine in 2003 as saying of Nxivm: “I think it’s a cult.”
He expanded on that opinion in an email to Ms. Bronfman, writing in an apparent reference to Ms. Snyder and Ms. Salzman “a young woman died in Alaska and some people blame Nancy’s diagnosis,” then criticizing the long hours that Nxivm courses typically lasted.
“Having the session go from 8:00 a.m. until 10:00 p.m. is extreme and it’s what cults do to gain dominance over their victims,” he wrote. “A group led by two people who call themselves Vanguard and Prefect certainly sounds like a cult.”