According to the U.S. agencies involved in the operations, AlphaBay vendors sold drugs such as fentanyl and heroin, and said "there have been multiple overdose deaths across the country attributed to purchases on the site". European law enforcement authorities say AlphaBay had more than 200,000 users, 40,000 vendors, with listings for more than 250,000 listings for drugs and other illicit substances.
Prior to the shutdown, Alexandre Cazes, a Canadian officials believe created AlphaBay, was arrested in Thailand by authorities working in cooperation with USA law enforcement. Investigators say AlphaBay was also a significant source of Fentanyl and Heroin linked to overdose deaths in the United States, including one in Portland, Oregon earlier this year.
It's still unclear how global law enforcement penetrated the two sites, both of which hid the location of their servers, administrators, and users with anonymity software like Tor and I2P.
According to Europol's press release, the European agency provided Dutch authorities with an investigation lead on the Hansa Market in 2016.
U.S. and European police announced on Thursday that they were responsible for the shutdown of two massive darknet marketplaces, AlphaBay and Hansa Market. "We recorded an eight times increase in the number of human users on Hansa immediately following the takedown of AlphaBay".
Then on July 4th, investigators made a strike against Alphabay, shutting down the site but not yet revealing their involvement, leading to speculation by its users that Alphabay's founder might have absconded with the funds.
According to Europol's "conservative estimation", around £1 billion (£770 million) worth of transactions have been process through the marketplace since its creation in 2014, all paid in crypto-currencies such as Bitcoin.
The Dutch National Police took over the Hansa marketplace on 20 June after two men in Germany were arrested and servers in Germany, The Netherlands and Lithuania were seized.
The FBI and DEA, meanwhile, say they identified a Canadian citizen who is alleged to have been the creator and administrator of AlphaBay. Each time business rebounded, as users again went in search of anonymous, online contraband sales.
"They coordinated a takedown and have punched a big hole in the operating ability of drug traffickers and other serious criminals around the world", Wainwright added. Though it's very hard to trace users on the dark web, on the markets buyers regularly use their own addresses when making a purchase. "For more information about this operation, please consult our hidden service at http://politiepcvh42eav.onion", Dutch authorities wrote on the seized Hansa website. With two out of the three largest marketplaces in the hands of law enforcement, anyone using The Dream Market will find it hard to dismiss the possibility that it is also compromised.