American authorities have arrested Konstantin Ignatov, leader of a cryptocurrency project called OneCoin. Prosecutors allege it was a pyramid scheme rather than a functional currency.

He was arrested on a wire fraud conspiracy charge, while his older sister, Ruja Ignatova, has been indicted for money laundering and wire and securities fraud.

The Bulgaria-based company, which was founded in 2014, still has operations running today. The company gave users a commission if they could convince others to buy OneCoin cryptocurrency, taking the familiar shape of a multi-level marketing scheme.

It claimed to have over three million members worldwide, despite having no functional blockchain or public ledger. Between 2014 and 2016, OneCoin made about $3.7 billion in revenue.

American government alleged that the leaders lied to investors to inflate the value of a OneCoin from half a euro to almost 30 euros as of January 2019. Meanwhile, the leaders of the project emailed each other saying that they planned on running off with the money.

In 2015, Ignatova started to give members of the project fake OneCoin tokens to sell, aptly calling them “fake coins.”

The company is known to be potentially fraudulent in a few countries, including in the UK, Germany, Finland, India, China, and Bulgaria.