A 25-year-old US citizen has been arrested in the US for allegedly selling a semi-automatic pistol to Dutch law enforcement officials in exchange for bitcoin.

This is according to the Amsterdam District Public Prosecutor, which revealed a semi-automatic weapon was purchased through an unidentified black market website on the supposedly anonymous Tor network.

The gun was sent disassembled, with its parts – including a silencer and laser pointer – concealed inside a DVD player, which allowed it to pass through customs.

Representatives from the Amsterdam District Public Prosecutor suggested that the US Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) is prosecuting the case stateside, but the agency refused requests for comment on the case.

The arrest marks the end of an investigation that began last summer, when Dutch police and the Public Prosecution Service in Amsterdam set out to purchase illegal goods with bitcoin. An English translation of the press release reads:

"Police and public prosecution wanted to investigate whether it is possible to purchase illegal products through the Tor network."

Tor networks have long provided anonymity to 'dark web' sites like Sheep Marketplace, Black Market Reloaded and Silk Road, which facilitate the sale of illegal goods such as firearms, as well as legal items.

Speaking to CoinDesk in December, Tor's creator Roger Dingledine estimated that roughly 800,000 people use the Tor network each day, and reiterated that many use it to access ordinary websites on the Internet.

Documents leaked last October by US whistleblower Edward Snowden suggest the Tor network is secure, having withstood years of attempted breaches by government hackers. However, reports have suggested the network is less effective at protecting individual users.

Though details about the new case remain scarce, the Public Prosecutor said the sender was already under surveillance by US law enforcement before the case began, a fact that perhaps contributed to the arrest. Further, the firearm was sent through standard mail, potentially providing another way for law enforcement to link the identity of the sender to the package.

Dutch officials say the purchase was made under an alias, and that the bitcoin payment was sent to a "trust account which the supplier believed to operate anonymously".

"The suspect will be brought to trial in the United States because of illegal weapon export," the statement continued.

The automatic pistol involved in the exchange is not illegal in the US, it concluded.

Gun Image via Shutterstock