In September 2019, the BBC reported the extraordinary story of Ruzha Ignatova, a Bulgarian wanted by the FBI after defrauding investors of $4.5 billion through her fake cryptocurrency before disappearing from the sight of her investors.
BBC Eye Investigations and Panorama looked into her close ties to a suspected Bulgarian organized crime boss and allegations that she was brutally murdered. Did Ignatova enjoy the stolen billions or was she killed by the people she was paid to protect her?
Oxford University graduate Ruza Ignatova was born in Bulgaria and raised in Germany, pursuing a successful career in finance before launching the cryptocurrency OneCoin in 2014.
To become a crypto queen, she convinced millions of people around the world to invest in OneCoin, promising to eclipse the huge returns seen by early Bitcoin investors.
But in reality, Ms. Ignatova - known to many as Dr. Ruzha - has created a cleverly disguised investment scam, without the digital record that underpins legitimate cryptocurrencies like Bitcoin.
As German and US investigators closed in on her, in October 2017 she took an early morning flight from Sofia to Athens, never to be seen again.
Over the past year, BBC World Service Eye Investigations and Panorama have been trying to find out more about what happened to her and whether she was even alive.
Key to this was establishing who her inner circle was.
Richard Reinhardt, who launched the OneCoin investigation for the US Internal Revenue Service along with the FBI, talked about a key character that investigators have never publicly named before. This is the man assigned the role of guarding Ignatova - Christophoros Nikos Amanatidis, better known as Taki.
„We were told that a known drug addict was allegedly responsible for her physical security,”, Reinhardt said in his first interview since retiring in late 2023.
„Taki appeared more than once, it was not a one-off. This was a recurring theme".
This matched the information we already had - US government lawyers said in 2019 that Ruzha Ignatova's head of security was a major organized crime figure in Bulgaria, but did not name him.
„We have evidence that a very significant, if not the most prolific drug trafficker of all time in Bulgaria, was closely associated with OneCoin – he served as her personal security”, the assistant attorney said.
This was the same “security chief” whom another US government official said was “involved in the disappearance” of Mrs. Ignatova in court a day earlier.
According to Mr. Reinhardt, Ms. Ignatova was a much more sophisticated criminal than most people imagine.
„It's like a white-collar criminal combined with a drug dealer or mobster on steroids.“
This theory appears to be supported by leaked Europol documents which show that before Ms Ignatova disappeared in 2017, Bulgarian police had established links between her and Taki.
In the documents, police suspect Taki of using OneCoin's financial network to launder the proceeds of drug trafficking.
In his native Bulgaria, Taki has an almost mythical status - El Chapo or Pablo Escobar. He is widely suspected of being the head of a Bulgarian organized crime organization and a drug smuggler. He and his associates were investigated there for armed robbery, drug smuggling and murder, but he was never successfully prosecuted for anything.
„When we talk about Taki, he is the boss of the mafia in Bulgaria. He is extremely strong,” says former Bulgarian Deputy Minister Ivan Hristanov, who in 2022 investigated allegations that Taki ran a criminal network with the help of corrupt officials – and believes that this is so.
„Such is the ghost. You will never see it. Only he is heard of. He speaks to you through other people. If you don't listen, you just disappear from the earth.”
„The only person who could protect Ignatova from all these investigations, including from foreign agencies", was Taki.
The BBC has written to the Bulgarian government about allegations of corrupt officials. It doesn't respond. The Metropolitan Prosecutor's Office says it "does not cover up crimes and persons who may have committed crimes.
Taki is now believed to be living in Dubai, where Ruzha Ignatova has bought a luxury penthouse and where tens of millions of dollars from the OneCoin scam have flowed into her bank accounts.
While it is not known how Taki and Ms. Ignatova met or whether he was involved with OneCoin from the beginning, multiple sources claim that they had a close personal relationship and that he was her daughter's godfather.
A Bulgarian source close to the crypto queen claims she may have been paying Taki up to €100,000 a month for protection. There appear to be other financial ties between Ms. Ignatova and Taki.
The Europol documents mention a complex deal for the sale of a plot of land on the Bulgarian Black Sea coast, which links one of Ms. Ignatova's companies to Taki's wife.
The documents were handed over to the secret police by Frank Schneider, a former spy and adviser to Ms. Ignatova, who has since also disappeared.
He told us that his old boss was working with “crooks” and “gangsters“.
Just a few months after he spoke, Frank Schneider also disappeared
When we interviewed Mr. Schneider at his home in France, he was under house arrest awaiting extradition to the US in connection with the OneCoin scam. However, he was not ready to reveal names.
„I won't tell you who because I have a family... This is real serious organized crime.“
In 2022, Bulgarian investigative journalist Dimitar Stoyanov and his colleagues from the investigative news publication bird.bg were handed a police report allegedly found in the home of a murdered Bulgarian policeman.
In the document, a police informant details how he overheard Taki's brother-in-law drunkenly say that Ms Ignatova was killed on Taki's orders in late 2018 and her body dismembered and dumped from a yacht in the Ionian Sea . Dimitar Stoyanov believes that this bill is “very, very possible”.
The authenticity of the police document has been confirmed by Bulgarian officials, and many of Taki's criminal associates believe the theory that he killed her is correct.
However, the BBC was unable to independently verify this claim.
The reasons are that the wanted Ms. Ignatova has become an unpleasant liability for Taki, who apparently wanted to remove his connections to the OneCoin scam.
Among the partners is Krasimir Kamenov, known as Kuro, wanted by Interpol for murder.
Dimitar Stoyanov says Curro told him he overheard Taki discussing his criminal business in front of Ms. Ignatova, and when Curro challenged Taki on whether he should do that, Taki replied: “Don't worry, she is as good as dead . ”
Kuro also claims to have spoken to the CIA about Taki, including the allegation that Taki ordered the assassination of the Crypto Queen. Sources close to Kuro confirmed to the BBC that this meeting took place in late 2022.
In May 2023, Kuro was murdered at his home in Cape Town, along with his wife and two others who worked for him. South African police are still looking for the killers, but Bulgarian former deputy minister Hristanov believes Kuro's murder is linked to Taki.
„Some people had to be removed because they knew too much about Taki".
„It was a sort of public execution that was more like a statement. Be careful who you deal with, he said.
Since publishing the allegations of Ignatova's murder, journalist Dimitar Stoyanov says he and his colleagues have faced death threats, forcing him to temporarily leave Bulgaria.
Stoyanov does not claim to know a motive for the alleged murder, but property records show, and eyewitnesses have told him, that after her disappearance, a number of Bulgarian properties are now being used by people connected to Taki.
Taki was never arrested on charges that he killed Ignatova. Her body has never been found and investigators say they don't have enough evidence to pursue him.
But former IRS investigator Richard Reinhardt thinks Ruzha Ignatova is probably dead. Although he hasn't seen any evidence linking her death to Taki, he says it's consistent with how drug cartels operate.
„There is no honor among thieves… knowing how cruel the cartels are, if Taki thought she was a threat to him… he probably would have liquidated her rather than let her be caught.“
The BBC has written to Taki's lawyers about the allegations in this investigation – they did not answer.
In 2022, Ms. Ignatova was placed on the FBI's Ten Most Wanted list - where she remains today, but it may be that the rumors of her death are just another brilliant maneuver to throw everyone off from the smell.
If that is the case, as the years go by it will probably become increasingly difficult for her to remain on the run.
„At one point it looks as if Elvis Presley might still be alive… This is really not very likely," says Hristanov.
According to Mr. Reinhardt, the FBI “doesn't keep people on the Top 10 list just for fun”. But they would only remove someone if there was “definitive proof” that they were dead. And under the circumstances, with Ruzha Ignatova it may never happen.
And that means, at least for now, that the missing crypto queen remains a hunted woman.