What DID happen to the world's most wanted woman who ran off with $6.3BILLION? Fresh light is cast on baffling mystery... with mafia mobsters claiming she was killed and thrown into the sea

In 2014, Dr Ruja Ignatova was taking great strides to becoming a household name. 

The flamboyant prophet of a promised technological revolution, millions globally trusted the Bulgarian-born entrepreneur with their life savings, showing unwavering faith in her vision for a new online currency. And then, in 2017, she disappeared without explanation.

Ten years on, there is still scarce detail on what happened to Dr Ruja. Authorities in the US charged her with fraud in absentia, believing her to have run off with $6.3billion worth of investments from supporters of her OneCoin cryptocurrency in some 175 countries. She remains the most wanted woman in the world.

Now, a groundbreaking investigation from the BBC has moved one step closer to solving the mystery of Dr Ruja's disappearance. Following the breadcrumbs back to her shady ties in Bulgaria, the question is asked: did she run away with the money, or was she killed by the very people that were supposed to protect her?

For seven years, the disappearance of the so-called 'CryptoQueen' has puzzled investigators, lost in a maze of dead ends as leads have vanished or washed up dead. But casting the mystery in a new light, investigators bravely examine Dr Ruja's alleged ties to suspected mafia connections - and new theories about why she left.

When Ruja Ignatova disappeared in October 2017 - failing to turn up to a meeting with promoters in Lisbon - her critics were already beginning to pick away at the integrity of her elaborate scam.

Early investors had bought into Dr Ruja's presentation as a glamorous Oxford-graduate who had allegedly spent six years with McKinsey before making the leap into the fledgling world of cryptocurrency. 

She was confident, well-dressed and assured her supporters her project, OneCoin, was about to take off. If the figures were to be believed, it was. Within months, millions of people worldwide had bought into the vision, purchasing packages of a new currency online that they believed would one day change the world.

In these years, Ruja never stayed out of the limelight. She was often pictured at photoshoots dressed elegantly, wearing her trademark red lipstick. As her audience grew, she made appearances at huge rallies. OneCoin even had a song referencing 'Ruja's revolution'. She was the celebrated face of a truly global movement.

Six years after the Global Financial Crisis, there was a sense of change in the air. Distrust in conventional banks and currency had created a new space for trust in cryptocurrencies, a 'revolutionary' new approach to money that sold itself on taking the power away from individuals and big companies.

Approached in the right way, it was safe, secure and invulnerable to manipulation from malicious actors. Those who got in fast had much to gain. 

In this space, the story of Bitcoin's astronomical rise - and the overnight fortunes it had created for early backers - was hard to miss. Very quickly, a new audience emerged of potential investors eager not to miss the boat a second time - and willing to take out huge loans to gamble on the viability of a relatively new technology.

OneCoin promised to be everything that Bitcoin was becoming. Anyone could buy 'packages' of the currency with real money and watch the value rise and rise. But there were key differences in the small print that would inevitably deter investors.

When Dr Ruja missed her meeting in October 2017, she was expected to finally address whether investors would be able to turn their virtual currency into euros. Concerns were mounting that investors buying 'packages' of the currency online could not exchange it for cash they could spend in shops. The value of their assets was rising - but there was no way of using it.

Crucially, investors were also slowly becoming aware that OneCoin lacked the safeguards needed to protect its value from manipulation. Bitcoin was backed up by a blockchain - essentially a ledger keeping a record of transactions and value changes that everybody has access to. The value could be secured and verified without having to relinquish control to a few greedy individuals.

Revelations that OneCoin was not, in fact, backed up by the blockchain were the first red flag - brought to light in a BBC investigative podcast series by Jamie Bartlett.

For years, Bartlett has sought to understand exactly what happened in those crucial months leading up to Ruja's disappearance. His podcast 'The Missing Cryptoqueen', has brought the story into focus since 2019, attracting thousands of listeners.

Now, he appears in the BBC Panorama story investigating new avenues as journalists and investigators continue their hunt for the world's most wanted woman. 'The Missing Cryptoqueen: Dead or Alive?' explores whether Ruja cleverly calculated her escape with $6.3billion worth of investors' money - or if she fell victim to a brutal mafia stab in the back.

Entire lives were destroyed in the wake of revelations not all was as it seemed with OneCoin. It took a long time for investors to realise what had happened, allowing the damage to multiply as people continued buying packages and refusing to heed the warnings.

Supporters had learned through careful messaging that OneCoin's critics were 'haters', that they were Bitcoin backers only annoyed that they had boarded the wrong train. 

Everybody else did not see the vision. Believers only needed to be patient.

And so when Ruja went missing in 2017, few wanted to entertain the possibility that there was no train at all.

In the 2019 podcast, Jamie Bartlett spoke to experts who discussed the scam in the same breath as cultic movements. 

It was not easy for people to decouple from the promise of revolution having already sunk so much into it. But for many families, their money would never be seen again. There was no revolution - or, if there was, it was not going to be through OneCoin.

By 2016, sources were beginning to raise suspicions that OneCoin was not backed up by a blockchain - as Ruja claimed it was. 

The value, in essence, was 'just a number that someone in an office in Bulgaria had made up and could delete just as easily', Jamie Bartlett assessed on the podcast at the time. 

When Ruja disappeared a year later, then, it made sense that she ran off with the money. She boarded a plane in Bulgaria with a bodyguard and flew to Athens. The bodyguard returned and she did not.

Soon after, she was charged with securities fraud, wire fraud and conspiracy to commit money-laundering in the US. 

In the judgment of the US justice department, OneCoin was 'an old-school pyramid scheme on a new-school platform'.

But incredibly, that was not the end of OneCoin. People continued to work the company from offices in Bulgaria. Properties belonging to Dr Ruja found new use.

So who were these people? 

In the wake of her departure, Konstantin Ignatov - her brother - stepped in to fill the void, according to prosecutors. Police swept in to arrest Ruja's cofounder Sebastian Greenwood in 2018, and nabbed Konstantin the following March.

Konstantin - deemed the 'de facto leader' of OneCoin - pleaded guilty to two counts of wire fraud, one count of bank fraud and one count of money laundering as part of a deal unsealed in New York in late 2019 and spent 34 months behind bars.

But still the lights stayed on. From 2019, Bartlett began to investigate rumours that Ruja's disappearance was part of a much larger, more elusive narrative of mafia dealings in Bulgaria.

In Bulgaria, they were warned away from probing too deeply, with bystanders afraid to be heard talking to the broadcaster for fear of reprisal. 

The BBC began working with a local journalists to piece together what really happened, what incentives Ruja would have to disappear, and who was pulling the strings in her absence.

More recently, local media has made tentative links between Ruja and Christoforos Amanatidis, a man in her native Bulgaria alleged to be the head of the country's organised crime network.

In 2022, documents seized from the house of an assassinated former police chief in Sofia revealed extraordinary claims that Ruja Ignatova was killed in November 2018 on behalf of Amanatidis.

The Missing Cryptoqueen: Dead or Alive? moves the story along five years, taking a step back to examine the case through a new lens.

Quizzing insiders and probing secret documents on her connections to the Bulgarian mafia, Panorama examines the evidence Ruja simply disappeared alongside claims from alleged mafia members she was killed near Greece, dismembered and thrown into the sea for 'knowing too much'.

With this, the dream of a currency revolution promised ten years ago is all but shattered by leads joining up to a web of spies, alleged crooked officials and serious criminals believed to have used this business as the façade of a much larger scheme.

What happened to Dr Ruja Ignatova may never be fully known or understood. But the mystery surrounding her sudden rise to fame, in stark contrast to her overnight withdrawal from the world, remains a curious artefact of the modern world - with a warning for all about the dangers of what happens in the shadows.

• The Missing Cryptoqueen: Dead or Alive? is on BBC One with an extended version on the BBC World Service YouTube channel now