An apartment building on the Upper East Side of Manhattan has been home for years to young models, girlfriends, pilots, and lawyers associated with multimillionaire sex offender Jeffrey Epstein.

Almost all the apartments in the building are owned by Epstein's brother, the real-estate developer Mark Epstein. He purchased them from the billionaire Leslie Wexner, Jeffrey Epstein's only known client.

Residents have repeatedly spotted former Israeli Prime Minister Ehud Barak visiting the building.

MC2, the modeling agency Epstein invested in, used the apartments to house overseas models. MC2's founder, Jean-Luc Brunel, had an apartment there.

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Before his extended stay in New York's Metropolitan Correctional Center began in July, disgraced sex offender Jeffrey Epstein dwelled in some of the city's most exclusive real estate, laying his head in a palatial Upper East Side townhouse and conducting his mysterious business out of a landmarked mansion on Madison Avenue.

But it hasn't been all private islands and 7,000-acre ranches for the half-billionaire. For decades Epstein has run some of his operations quietly out of a squat Second Avenue residential building owned by his brother, Mark Epstein, and frequently visited by the former Israeli Prime Minister Ehud Barak.

According to property records and court filings, Jeffrey Epstein has long housed girlfriends, associates, employees, and businesses in a handful of units at 301 East 66th St. There are 200 units at the address, and the majority of them are owned on paper by his brother's development firm, Ossa Properties. While Ossa nominally owns the units connected to Jeffrey Epstein, the aforementioned records and filings show that Epstein effectively controls them.

A light-filled lobby on a less upscale block

The postwar white-brick high-rise sits atop a nail salon, a coffee shop, and an Italian restaurant along a traffic-choked stretch of Second Avenue. Topped by a green canopy, the front door opens to a doorman guarding a hallway that leads to a light-filled lobby decorated with two couches and an armchair. Though the building shares a ZIP code with Epstein's townhouse, its share of the neighborhood east of Park Avenue is less upscale, catering more to families and young professionals than foreign heads of state.

Some of Epstein's activity at the apartment building appears to be business-related: New York state corporate registrations tie 9 East 71, an LLC named after his townhouse, and NES LLC, which owns the townhouse and pays his pilots' paychecks, to the building.

Over the years, he's assigned units in the building to his house managers, and used two one-bedrooms to house his pilots during New York layovers. In the next-door garage, attached to 301 East 66th St. by a private entrance, he stored a Chevrolet Tahoe.

The agency that Epstein invested in housed underage models '4 girls to an apartment'

Over the years, a number of Epstein's friends have also called 301 East 66th St. home, including his ex-girlfriend, the socialite Eva Andersson (who is now married to hedge-fund star and Epstein confidant Glenn Dubin), and his former business partner, MC2 Models founder Jean-Luc Brunel. (According to a Page Six report, the modeling agency was named after Einstein's famous equation, with the missing "E" standing for Epstein. "He thinks everyone is too dumb to figure it out," the paper said.)

Then there were the underage models. Many of them were foreign and scouted by Brunel, according to a 2010 deposition given by a former MC2 bookkeeper named Maritza Vasquez. (Vasquez could not be reached for comment but her sworn statement was supported by Epstein's former house manager, Alfredo Rodriguez, whose annotations of Epstein's address book include "Apt. for models" next to the 66th Street entry.)

"I know that the models were staying in different apartments belonging to Jeffrey Epstein," Vasquez said in her deposition. "There is not only one girl. There is not only one apartment. I believe there were like, two or three apartments. And they were put in between four girls per apartment."

All 4 of the named 'coconspirators' in Epstein's plea deal have been associated with the building

Vasquez said part of her job was helping to obtain visas for the girls, and she recalled fielding an angry call from Epstein after a model visa application for a 14-year-old, Nadia Marcinkova, fell through. Part of the problem, Vasquez said, was she wasn't really a model.

"That girl never work, she was never a model. She was living in his place but she disappear," Vasquez said she was told by a coworker who worked directly on the application. "She never actually even worked as a model."

Indeed, according to a Palm Beach Police Department report from 2006, Epstein told one of his victims that Marcinkova was a "sex slave" he had purchased from her parents in Yugoslavia when she was a teen. According to the report, Marcinkova frequently participated in sexual acts with Epstein and his underage victims.

By 2007, she was 22 and working as an assistant for Epstein when she and three other women were granted immunity as possible coconspirators in his controversial plea deal with federal prosecutors. Records show that all the women named in that agreement, who were accused of helping to coordinate or physically participating in Epstein's sex trafficking operation — Marcinkova, Sarah Kellen, Adriana Ross, Lesley Groff — shared something else in common: the 66th St. address.

It's not clear when Ross left the building, but Groff was still operating out of a 10th-floor unit as Epstein's assistant and an employee of NES LLC, in 2009, according to a deposition given that year by Epstein's pilot, Larry Visoski. (The company, now registered in the Virgin Islands, is still active. In March, after a judge invalidated Epstein's plea deal, someone operating as NES LLC shipped a 193-pound tile and carpet extractor from Epstein's private island to his Manhattan townhouse.)

Epstein's longtime lawyer has a corporate address there too

Both Kellen and Marcinkova (who later shortened her name to Marcinko) continued to live or work at 301 East 66th St. for the next decade, records show. The building is the active registration address for Marcinko's company, Aviloop, and was listed as the delivery address for Kellen's company, SLK Designs, up until this month. A group of young model types photographed with Epstein in 2016 have also been linked to the building, according to public records databases.

According to court documents and his attorney-registration files, Epstein's lawyer, Darren Indyke, used a 10th-floor unit as his primary office address for nearly a decade; he also used the address to receive mail for his corporation, DKI PLLC. It was later listed as the point of contact for Epstein's private foundation in 2008, the same year Epstein began serving out his sentence in Palm Beach.

An entry for 301 East 66th Street in Epstein's "little black book." Jeffrey Epstein's Little Black Book

One of Epstein's units, previously linked to Marcinko and listed as a mailing address for a number of Epstein ventures, is now home to the studio of Joyce Anderson, a fashion photographer who specializes in headshots and "children/pre-teen sessions," according to her website.

She's been there since 2007, when she moved her studio from 30 Vandam Street — another building owned by Mark Epstein. (The Vandam Street building, a mixed-use six-story structure in Manhattan's Hudson Square, is also where a company called "Saint Model and Talent" was registered to Mark Epstein in 2005, business records show. According to the New York Department of State's Division of Corporations, it is still active, although there's no public trace that it operates.)

Anderson and Mark Epstein made a joint donation to a New School scholarship fund in 2007, and appear to have a longstanding relationship. Reached by phone, Anderson declined to comment on her work as a photographer or her connection to the Epstein brothers, saying: "I have no information to offer you. Have yourself a wonderful day, thank you." After this post was published, Mark Epstein clarified in an email that Anderson is his "ex" and that she had "no relationship with Jeffrey and never worked for him."

Former Israeli Prime Minister Ehud Barak visited 'often'

Former Israeli Prime Minister Ehud Barak hasn't been photographed entering or leaving 301 East 66th St., like he was outside Epstein's infamous townhouse in 2016, but he made an impression nonetheless. Residents say he has been periodically visiting the building for years.

One former resident says she "often" saw Barak and his security detail in the building, with a sighting as recent as this calendar year. Another former resident, who confirmed Barak was a frequent visitor, said he once accidentally rode the elevator with Barak and two unfriendly security guards after sliding in through the doors at the last second.

Barak's presence in the building was often announced to residents by way of a visible security detail with Suburbans idling on the street outside, witnesses say. One source who visited the building in 2017 recalls seeing what the source described as "Mossad agents" — meaning Israeli security guards — waiting downstairs, and former residents said at least one member of the security team would typically be posted in the lobby with an earpiece when Barak was upstairs. On at least one occasion, the former resident said, NYPD officers were also stationed outside.

Barak's name and contact information appeared in Epstein's "little black book," which Gawker published in 2015. His name had been circled by Rodriguez, the house manager who had stolen it and tried to sell it to lawyers representing Epstein's victims. According to The Washington Post, Rodriguez told FBI agents that he had circled the names of "witnesses" to Epstein's activities.

Barak admitted to the Daily Beast last month that he had visited two of Epstein's Manhattan residences and his private island but denied meeting any girls there. He kept the details otherwise vague, telling the outlet that he and Epstein ultimately met "more than 10 times and much less than a hundred times, but I can't tell you exactly how many. I don't keep count."

Barak didn't mention the state of Florida in his statement, but Alan Dershowitz testified in a 2015 deposition that Epstein maintained a suite of guest bedrooms in his Palm Beach home, which were "assigned to people like Senator George Mitchell, Ehud Barak, prominent guests who would stay in his house."

Barak is now reportedly working to dissolve a limited partnership he formed with Epstein in 2015, saying he didn't realize at the time of their agreement that Epstein's crimes involved minors. A spokesperson for Barak did not respond to a request for comment.

A doorman on duty at the building last week confirmed seeing security details outside, but said he wouldn't be able to determine if any visitors to the building were underage, suggesting at one point that a 30-year-old reporter standing in the lobby could be a teenager for all he knew.

Mark Epstein says he has nothing to do with his brother's businesses or alleged sex trafficking

Epstein's brother, Mark, has also long denied any knowledge of his brother's activities in the building.

"I don't live in that building, I don't monitor who uses those apartments," he told Crains New York last month. "I'm not sure who pays it, but Jeff's been renting there for years."

Reached by phone, Mark declined to answer any questions, referring a reporter to previous statements before abruptly hanging up. In response to an emailed list of questions, he wrote, "We didn't get disconnected, I hung up on you. Be clear about that."

But in the interview with Crains New York, Mark denied any business crossover between his company, Ossa Properties, and his brother. When a 2004 Harlem charter school filing characterized Ossa as "an affiliated NYC real estate investment company" of his brother's investment firm, J. Epstein & Co., he characterized it as a "mistake."

"There's no business relationship between those entities," he told the newspaper. But records show at least two 1991 filings where Ossa's address is listed as "475 Madison Avenue" — the home of J. Epstein & Co. and a charitable foundation named "Epstein Interests." It's also the same office where Jeffrey Epstein's attorney, Darren Indyke, first registered a company called E Management. According to court documents, E Management was operated by Brunel, the owner of MC2.

Mark Epstein purchased his units from Leslie Wexner, his brother's only known client

The $70 million townhouse on 71st Street was apparently given to Epstein by billionaire Les Wexler. Hollis Johnson/Business Insider

Since its inception in the early 1980s, J. Epstein & Co. has had only one public client — the billionaire Les Wexner, who apparently gave Epstein the $70 million townhouse he now calls home before their personal and professional affiliation ended in 2007.

It turns out that the mansion isn't the only patch of New York real estate that Wexner transferred to an Epstein: Mark told Crains New York that he bought the units at 301 East 66th St. in the early 1990s from Wexner. His brother tipped him to the opportunity.

But a former classmate of Epstein's interviewed in James Patterson's book "Filthy Rich" made it sound like more of a partnership.

"He was a diamond in the rough, you see," Gary Grossberg told Patterson. "People recognized Jeffrey's brilliance very early on. But he had a gift for recognizing opportunities very quickly. He started buying properties in Manhattan, including 301 East 66th St. He asked his brother — did Mark want to join him? He did."

With additional reporting by John Cook and J.K. Trotter.

Do you have a story to share about Jeffrey Epstein, his brother Mark, or 301 E. 66th St.? Contact this reporter at gabriellebluestone@gmail.com.