Four UK men were arrested on Tuesday for their part in the multi-million pound illicit Silk Road marketplace.
The men – three of whom were in their early 20s and from Manchester, and one of which was in his early 50s from Devon – were arrested by the newly-operational National Crime Agency (NCA), a British equivalent of the FBI. They have been described as "significant users" of the site, and are thought to be suppliers of drugs over the network.
The Silk Road website, which was hidden deep within secretive, anonymous Tor networks, was one of the world's largest websites for the distribution of drugs, weapons and other illegal material until it was shut down by the FBI last week. It mimicked eBay-style seller ratings, and used the traditional postal service to distribute controlled substances.
Its creator and operator, Ross Ulbricht - who went by the online handle "Dread Pirate Roberts" - appeared in a San Francisco court on Friday. He pleaded not guilty to all charges, and was subsequently denied bail as a flight risk.
The FBI is currently working to decrypt the Dread Pirate's Bitcoin wallet, which was seized during the raids and contains 600,000 of the currency - an equivalent of £49.7 million.
The UK arrests are part of a global swoop to seize major players in the Silk Road network. A couple were arrested in Washington State on suspicion of being behind the vendor "NOD", one of the most active selling accounts on the site with more than 1,400 customer reviews after shifting more than 2,600g of cocaine and 600g of heroin. Two more men were arrested in Sweden for selling cannabis over the network.
Keith Bristow, the NCA's Director General, said in a statement: "These arrests send a clear message to criminals; the hidden Internet isn't hidden and your anonymous activity isn't anonymous. We know where you are, what you are doing and we will catch you."
"It is impossible for criminals to completely erase their digital footprint. No matter how technology-savvy the offender, they will always make mistakes and this brings law enforcement closer to them."
He went on to name Tor networks as one of the main targets for the newly-formed agency.
"These so called hidden or anonymous online environments are a key priority for the National Crime Agency. Using the expertise of over 4,000 officers and the latest technology, we will arrest suspects and disrupt and prevent their illegal activity to protect the public.
Tor networks, which were originally referred to as "onion routing" due to the layers of encryption involved, makes users' Internet use difficult to trace by directing it through a worldwide network of more than three thousand relays.
While the networks are used in some countries as a means to circumvent harsh censorship or laws or to organise protest, they are also a haven for all kinds of illegal activity, from drug smuggling to copyright infringement and the distribution of child pornography.
Bristow went on to say that the unravelling of the Silk Road had only just begun.
"These latest arrests are just the start; there are many more to come."
Image: NCA; Flickr (DavidQuick)