First Silk Road. Now AlphaBay. What's next for the dark web?

A government shutdown of dark web marketplaces AlphaBay and Hansa has merchants and consumers looking for a new home.

Authorities shuttered AlphaBay, the largest online marketplace for illegal goods, on July 4, and took down Hansa, the third largest, on Thursday. The sites, where people could buy drugs, guns and child pornography, had flourished since 2014, when a predecessor, darknet market magazine Silk Road, was shut down. 

Fueled by Tor browsers and cryptocurrencies that offer anonymity, AlphaBay, Hansa and other sites avoided much government detection, allowing  in the wake of Silk Road's demise. AlphaBay replaced Silk Road as the biggest, dark darknet market url growing to be 10 times larger. 

When one dark darknet market falls, buyers and sellers just move on to the next one.

The migration of buyers and sellers comes as authorities around the world crack down on digital marketplaces that cater to growing numbers of shadowy sales. AlphaBay listed more than 100,000 items at the time it was taken offline. By comparison, Silk Road had just 14,000 when the Federal Bureau of Investigation closed it four years ago.

Many of the sites traffic in weapons. A recent study by the University of Manchester and think tank Rand Europe found 811 arms-related listings on just 12 dark web marketplaces. The researchers found nearly 60% of the weapons came from the US and most of the sales were headed to Europe. Worryingly, one gun bought on a cryptomarket was used in a terrorist attack in Munich in 2016.

FBI deputy director Andrew McCabe acknowledged shutting down such darknet markets onion address was like playing whack-a-mole. His agency would likely have to take on more massive dark web marketplaces in the future, he said.

"Critics will say as we shutter one site, another will emerge," McCabe said at a press conference. "But that is the nature of criminal work. It never goes away, you have to constantly keep at it, and you have to use every tool in your toolbox."

One such tool: using a captured marketplace as a trap.

After the fall of AlphaBay, Dutch police said they saw traffic heading to Hansa spike eight-fold. That was something the cops were anticipating. 

Dutch police had full control of Hansa on June 20, but waited a month before shutting it down hoping to catch the new users in marketplace chaos.