During Jeffrey Epstein's first spell in jail, a 13-month sentence for soliciting sex from an under-age girl, prison records show one woman visited him at least 67 times.
That woman was Nadia Marcinko. Marcinko was Epstein's main girlfriend for seven years - his most significant partner after Ghislaine Maxwell - and in later years, an assistant pilot of his private plane.
She is comparatively unknown to the public, but she may soon find herself in the spotlight.
Marcinko is one of four women who were named as Epstein's potential co-conspirators in a 2008 plea deal that granted them immunity from prosecution. Now, two of those women - Epstein assistants Sarah Kellen and Lesley Groff - are about to be questioned by US legislators. One congresswoman wants all four, including Adriana Ross, another Epstein assistant, and Marcinko, to be investigated, despite the plea deal.
Marcinko has never been accused of, or charged with, any crime. Her lawyers say she is one of Epstein's victims. But girls in Palm Beach, Florida, whose testimony about their abuse when they were under age led to Epstein's conviction in 2008, told police that Marcinko participated in that abuse.
The BBC has spent months interviewing those who have met Marcinko and scrutinizing every email we could find between her and Epstein in the files, to try and build a detailed picture of her role in the disgraced financier's life.
The emails reveal Epstein and Marcinko wanted to start a family together, we have discovered. The BBC has also found evidence suggesting that over many years, he asked her to recruit other women to help satisfy his sexual desires and she complied.
But the emails also expose deeply coercive tendencies on the part of Epstein. Marcinko later told investigators that he was physically violent, choking her, and throwing her down a flight of stairs. We have had access to her account to investigators via a document that was released - heavily redacted - by the US Department of Justice in January. Marcinko's name is not visible, but the five pages of testimony match in every detail what we know about her from other sources.
The BBC contacted Marcinko for comment, but she did not reply. Since Epstein's death in prison in 2019, awaiting further sex charges, she has disappeared from public view.
The calls for an investigation into Marcinko have raised important questions about whether a victim of sexual coercion can also be deemed an accomplice.
Marcinko was born Nadia Marcinkova into a comfortably-off, respected family in Slovakia. She told federal investigators who interviewed her after Epstein's death that she had first met the financier in New York in 2003, when she was 18, at a birthday party for Jean-Luc Brunel.
This seems to be backed up by email chains the BBC has traced in the Epstein files, which reveal that for many years afterward, Marcinko and Epstein celebrated the same date - 17 September - as their anniversary.
Marcinko was an unlikely international model, says a primary school classmate who we are calling Jozef. Though she was beautiful, she was very shy - what we call šedá myška, a little grey mouse.
She began modeling as a teenager, with assignments soon taking her to Japan and Taiwan, she once told a Slovak newspaper.
A few days after she first met Epstein at Brunel's party, Epstein invited her to his mansion in Palm Beach, Marcinko told investigators. And from there, flight logs confirm, she went on to his private Caribbean island, Little St James.
She was legally an adult, but the imbalance between them in power, wealth, and age was huge. Epstein was already 50, so 32 years her senior.
Because Brunel sponsored her visa, and because Epstein bankrolled Brunel's agency - to the tune of a million dollars - she felt, she later told investigators, that Epstein could have her deported with a single phone call to Brunel.
She traveled with him constantly, she told investigators. And emails, both in their tone and content, suggest they rapidly became a couple. Ghislaine Maxwell was still Epstein's close friend and was finding other women for him, but their sexual relationship was coming to an end, our research suggests. Marcinko was now his main girlfriend, the emails show.
But though there is plenty of sentiment in the emails - and Epstein writes to someone else in 2009 that I am in love with nadia - the exchanges also reveal how domineering he was.
After his death, Marcinko told investigators Epstein had controlled every aspect of her life, including her weight and clothing. She said he had forced her to have multiple plastic surgeries and physically abused her.
However, while Marcinko appears to have been loyal to Epstein for years, in 2018 she switched sides. A document in the files describes how she began to co-operate with the FBI that year in its investigation. The following year, Epstein was jailed again while he awaited sex trafficking charges. In return, four years later, the FBI supported Marcinko's application to stay in the US after her visa ran out in 2022. The agency said she had been recruited, harbored and obtained by Jeffrey Epstein and others for purposes of a coercive sexual relationship.
