According to the US DoJ (Department of Justice), a total of fifteen people pleaded guilty to an international fraud ring case involving Bitcoin. From 2013, this international fraud ring utilized website listings like cars to manipulate its American victims. The group would then launder the money via Coinflux (a fiat-to-crypto exchange in Romania).
According to the statement, it appears that the fifteen criminals thought they would be invincible when they did all these criminal actions over the years. However, through international investigation and cooperation, they've finally been brought to justice.
Their downfall began in December 2018, when Coinflux founder himself was arrested for money laundry and fraud charges. He was then forced to fly to the US to serve his jail time over there. Since then, the investigation kept going, and the US DoJ successfully forced other involved criminals to admit their crimes.
Cases like this are very much rampant in the crypto space. There have been plenty of cases where criminals use Bitcoin and even Monero (XMR) to launder money from illegal activities. While some criminals are still free, many cases involving US victims have been successfully investigated through international cooperation.
Source: CoinTelegraph