At least 288 people were arrested and 50.8 million euros or more than $56 million in cash and cryptocurrency were seized by the U.S. and law enforcement agencies across eight countries in an unprecedented dark web drug enforcement action dubbed Operation Spector.

The operation also resulted in the seizure of a dark-web marketplace called Monopoly Market, Attorney General Merrick Garland said in a press conference Tuesday. The arrested individuals were allegedly selling firearms and drugs through the illegal marketplace and other similar websites. At least 153 of them were arrested in the United States, 55 in the United Kingdom and 52 in Germany.

Among those arrested was a California man who allegedly sold more than $2 million worth of the popular opioid Fentanyl and recreational drug methamphetamines on the dark web. The remaining arrests were made in Austria, France, Poland, Switzerland and the Netherlands.

"The Justice Department is cracking down on criminal cryptocurrency transactions," Garland said, and "the online criminal marketplaces that enable them."

Monopoly Marketplace was launched in 2019 and was seized by German authorities in December 2021.

"Europol has been compiling intelligence packages based on troves of evidence provided by German authorities, who successfully seized the marketplace's criminal infrastructure in December 2021," the European agency shared in a press release.

Aside from the arrests, Operation Spector, which started in October 2021, also resulted in the seizure of more than 850 kilograms of drugs, including "over 258 kg of amphetamines, 43 kg of cocaine, 43 kg of MDMA and over 10 kg of LSD and ecstasy pills, and 117 firearms."

"Our message to criminals on the dark web is this: You can try to hide in the furthest reaches of the internet, but the Justice Department will find you and hold you accountable for your crimes," Garland said.

Operation Spector, according to Europol, was a part of the same undertaking that took down the Hydra and Genesis Market in 2022 and 2023, respectively.

Hydra used to be the largest illicit marketplace on the dark web at the time while Genesis used to be the largest identity theft market in the overlay network within the internet accessible only by a specialized web browser.

"Our coalition of law enforcement authorities across three continents proves that we all do better when we work together," Europol's Executive Director Catherine De Bolle said, noting that "this operation sends a strong message to criminals on the dark web: international law enforcement has the means and the ability to identify and hold you accountable for your illegal activities, even on the dark web."

Last month, the U.S. Department of Justice (DOJ) announced the sentencing of James Zhong, the alleged Silk Road hacker who once possessed around $3 billion worth of crypto assets.

In a verdict announced by United States District Judge Paul G. Gardephe, Zhong was sentenced to "one year and one day in prison for committing wire fraud in September 2012 when he unlawfully obtained approximately 50,000 Bitcoin from the Silk Road," the Justice Department press release read.

Europol announced it had coordinated an operation involving nine countries to seize 'Monopoly Market' with 288 people arrested for selling drugs on the illegal dark web marketplace