US and European police on Thursday announced the shutdown of two huge "dark web" marketplaces that allowed the anonymous online trade of drugs, hacking software and guns.
US Attorney General Jeff Sessions said underground websites AlphaBay and Hansa had tens of thousands of sellers of deadly drugs like fentanyl and other illicit goods serving more than 200,000 customers worldwide.
"This case, pursued by dedicated agents and prosecutors, says you are not safe, you cannot hide. We will find you, dismantle your organization and network, and we will prosecute you," Sessions said in a warning to dark web entrepreneurs.
The announcement came three weeks after AlphaBay stopped functioning with no explanation.
On July 5, the Canadian national who ran AlphaBay, Alexandre Cazes, was arrested in Thailand. Earlier this week, Cazes was found dead in his Thai police cell, with police saying he apparently hanged himself with a towel.
AlphaBay's shutdown sent traffic flooding into the smaller Hansa marketplace.
But that new traffic, tens of thousands of users, was unaware that Dutch police had already secretly taken control of Hansa, giving them the ability to identify and track buyers and sellers of illicit goods.
The Hansa market has also now been shut down, said Europol executive director Rob Wainwright.
"By acting together on a global basis the law enforcement community has sent a clear message that we have the means to identify criminality and strike back, even in areas of the Dark Web," Wainwright said.
AlphaBay had been a massive marketplace for illicit goods, 10 times larger than the notorious Silk Road underground cyber marketplace shut down by the US Federal Bureau of Investigation in 2013.
At the time it was shut down, it had more than 250,000 listings for illegal drugs and toxic chemicals, according to the US Justice Department.
It also had 100,000 advertisements for guns, stolen and fraudulent personal documents, counterfeit goods, malware and computer hacking tools.
The marketplaces operated underground on the Tor network, which allows anonymity for users.
With the takedown of AlphaBay and Hansa, authorities said they have frozen millions of dollars worth of cryptocurrencies like Bitcoin used to settle online transactions without the buyers and sellers being identified.
They also seized from Cazes and his wife millions of dollars in currency, luxury cars, and homes in four countries, including a hotel he owned in Thailand.
Wainwright said the investigation had resulted in the identification of numerous organized crime figures and that intelligence leads have been distributed to law enforcement in 37 countries around the world.
"This operation is an example of the improving concerted ability of law enforcement to strike against criminals, even on the dark net," he said.
"This coordinated hit against these two marketplaces is just a taste of what is to come in the future."
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