Two of the largest dark web marketplaces have been shut down following a “landmark” international law enforcement investigation.
The AlphaBay and Hansa sites had been associated with the trade in illicit items such as drugs, weapons, malware and stolen data.
According to Europol, there were more than 250,000 listings for illegal drugs and toxic chemicals on AlphaBay.
Hansa was seized and covertly monitored for a month before being deactivated.
The agency said it believed the bust would lead to hundreds of new investigations in Europe.
“The capability of drug traffickers and other serious criminals around the world has taken a serious hit today,” said Europol’s executive director Rob Wainwright.
It was a “landmark” operation, according to US Federal Bureau of Investigation (FBI) acting director Andrew McCabe.
AlphaBay has been offline since early July, fuelling suspicions among users that a law enforcement crackdown had taken place.
“We know of several Americans who were killed by drugs on AlphaBay,” said US Attorney General Jeff Sessions.
“One victim was just 18 years old when in February she overdosed on a powerful synthetic opioid which she had bought on AlphaBay.”
He also said a 13-year-old boy died after overdosing on a synthetic opioid bought by a high school classmate via the site.
Mr Sessions cautioned criminals from thinking that they could evade prosecution by using the dark web: “You cannot hide,” he said, “We will find you.”