July 20 (UPI) -- Federal authorities on Thursday announced that AlphaBay, one of the largest "dark net" Internet sites used to sell illegal drugs and contraband, was shut down and its founder was arrested in Thailand.
U.S. Attorney General Jeff Sessions said AlphaBay had grown in size to more than 250,000 listings for illegal narcotics via cryptocurrencies, such as bitcoin, that help users remain anonymous.
Prior to the shutdown, Alexandre Cazes, a Canadian officials believe created AlphaBay, was arrested in Thailand by authorities working in cooperation with U.S. law enforcement. Cazes was the subject of a multi-count racketeering and drug sales indictment filed by the U.S. attorney for the eastern district of California.
The U.S. Justice Department said Cazes then killed himself while in Thai custody.
"This is likely one of the most important criminal investigations of the year -- taking down the largest dark net marketplace in history," Sessions said in a statement Thursday.
Federal agents said they seized millions in cryptocurrency and a huge stash of luxury goods, including homes, boats and sports cars they said were all purchased by Cazes and his wife using profits from AlphaBay.
"Make no mistake, the forces of law and justice face a new challenge from the criminals and transnational criminal organizations who think they can commit their crimes with impunity using the dark net," Sessions added. "The dark net is not a place to hide. The Department will continue to find, arrest, prosecute, convict, and incarcerate criminals, drug traffickers and their enablers wherever they are.
"I believe that because of this operation, the American people are safer -- safer from the threat of identity fraud and malware, and safer from deadly drugs."
Officials said they believe AlphaBay had facilitated about $1 billion in black market sales since its creation three years ago.
Two of the drug traffickers on the website have also been identified and charged after heroin and a synthetic opiate purchased on AlphaBay were linked to overdose deaths in Oregon and Florida.
A second dark net site, Hansa, was also shut down as part of the operation. U.S. law enforcement working with their counterparts in the Netherlands and with the continent-wide law enforcement agency Europol, were able to identify the individuals behind Hansa and shut it down.
Dutch authorities were able to take control of the Hansa site on June 20 and allowed it to continue operating in order to gain information about those using it to traffic illegal drugs and weapons. The site was shut down on Thursday.