The US Department of Justice has charged Keonne Rodriguez and William Lonergan Hill, the founders of Samourai, a cryptocurrency mixing service, for allegedly laundering over $100 million from various criminal enterprises over almost a decade.

According to the DoJ, since 2015, Samourai Wallet has been used by cybercriminals as a means to launder illicit funds, masquerading as a legitimate privacy-oriented service.

Rodriguez is expected to appear in a US court, while Hill awaits extradition following his apprehension in Portugal on Wednesday. The charges against them stem from their alleged involvement in developing, marketing, and operating a cryptocurrency mixer that facilitated over $2 billion in unlawful transactions, with more than $100 million involved in money laundering transactions from illegal dark web markets such as Silk Road and Hydra Market.

The Rodriguez and Hill are accused of implementing features in Samourai Wallet designed to aid criminals in engaging in large-scale money laundering and sanctions evasion. The duo are facing charges of conspiracy to commit money laundering and conspiracy to operate an unlicensed money transmitting business.

Rodriguez and Hill also operated Twitter accounts that openly encouraged users to launder criminal proceeds through Samourai, according to the DoJ.

The DoJ said that Rodriguez and Hill earned millions of dollars in fees from Samourai, which combined various unique features to execute anonymous financial transactions for its customers.

For instance, the mixing service, known as “Whirlpool,” coordinated batches of cryptocurrency exchanges among groups of Samourai users to prevent tracing of criminal proceeds by law enforcement on the Blockchain. Another service offered by Samourai, called “Ricochet,” allowed users to build in additional and unnecessary intermediate transactions, making it challenging for law enforcement and cryptocurrency exchanges to identify the origins of the funds.

Since the inception of Whirlpool in 2019 and Ricochet in 2017, over 80,000 BTC (worth over $2 billion) has passed through these services. Samourai collected fees for both services, estimated at about $3.4 million for Whirlpool transactions and $1.1 million for Ricochet transactions over the same period.

In a coordinated effort with law enforcement authorities in Iceland, Samourai's web servers and domain were seized. Additionally, a seizure warrant for Samourai's mobile application was served on the Google Play Store.