The US Attorney-General Jeff Sessions had a press conference detailing AlphaBay, Hansa and the requested arrest and extradition of Cazes.
Hansa was frequently mentioned, meaning that the authorities were likely able to uncover new criminal activity on Hansa as users migrated to it from AlphaBay.
Scouring the sites, the researchers found 811 different listings from 52 distinct vendors offering weapons or related items like ammunition and explosives, according to the report.
"This is the largest dark net marketplace takedown in history", Sessions stated on Thursday. "You can not hide. We will find you".
AlphaBay and Hansa after the takedown.
Cazes, a Canadian citizen, was arrested in Thailand on July 5, but he committed suicide while in custody a week later. Cazes was found dead last week in his cell and apparently took his own life. But on Thursday, European law enforcement revealed that a second darknet site known as Hansa had also been in police hands for the past month, an announcement deliberately created to sow panic among tech-savvy dealers and buyers. Rob Wainwright, the director of Europol, said in Washington on Thursday. As of June 20 this year, the Dutch police had secretly taken control of the site. In addition, Dutch police have passed 10,000 non-Dutch mailing addresses tied to Hansa market buyers to Europol.
Law enforcement officials have struggled for years to crack down on these marketplaces, which are hard to locate because their software is distributed across the Tor network, which anonymises users and makes them nearly impossible to track.
This story will be updated throughout the day.
"The e-mail address of "firstname.lastname@example.org" was included in the header information of the AlphaBay welcome e-mail", the court filing continues.
The AlphaBay and Hansa websites had been used to trade illegal drugs, firearms, malware, stolen and fraudulent identity documents and more. Hansa Market was open earlier this week and announced that it was planning to ban fentanyl from the site. They then sat back and captured the identities of "all those new users displaced from AlphaBay who were looking for a new trading platform", Europe says. "What we have seen in the past is that people move around".
Andrew McCabe, acting director of the Federal Bureau of Investigation, called this a "landmark operation" as "Alpha Bay was roughly ten times the size of the Silk Road, so we are talking about multiple servers, different countries, hundreds of millions of dollars in crypto currency, in a dark net drug trade that spans the globe". Hacking away at individual walls and beams only does so much. "We will find you, dismantle your organization and network, and we will prosecute you", Sessions said in a warning to dark web entrepreneurs.
"This operation is an example of the improving concerted ability of law enforcement to strike against criminals, even on the dark net", he said.
The takedown follows the shutdown of the original Silk Road marketplace in 2013, and its 2015 successor. "LE may have won this battle, but they will NEVER win the war on drugs", noted one poster on Reddit's darknet forum.
Darknet marketplaces have generated massive police heat after unsafe synthetic drugs, such as fentanyl - the substance at the heart of drug epidemics in multiple countries, including Canada and the United States - were constantly offered for sale on the websites.