Police in Denmark are claiming to have achieved a world first, hunting down Internet drug traffickers by analyzing bitcoin transactions.

According to local media, The Danish National Police Cyber Crime Center, or NC3, has developed a new toolkit that has now been used to prosecute two drug traffickers in separate cases.

In one case in January in the Danish city of Herning, prosecutors used bitcoin-tracing evidence to catch the defendant, who stood accused of buying large amounts of amphetamines, cocaine and ketamine on online marketplaces via encrypted websites on the dark web. The man was found guilty and sentenced to eight years in prison.

How the toolkit works is not entirely clear. Both cases involved an initial discovery of illegal substances in mail letters and packages before the investigation began. But the report does note that bitcoin is recorded to the blockchain, suggesting that the toolkit is able to track transactions across the blockchain, leading to the person purchasing the illicit items.

“All transfers that have ever been made are coded into the bitcoin-system. Therefore, you can at any given time log in and search in the system and try to identify individual users,” a prosecutor is reported to have said.

The report goes on to claim that NC3’s new breakthrough has attracted interest from the U.S. Federal Bureau of Investigation and the international crime-fighting organization Interpol. “We are pretty much unique in the world at this moment, because nobody else has been able to use this type of trace as evidence before,” an NC3 spokesman said. “Everybody is looking towards Denmark in this field, and we are in close dialog with several other countries at the moment, so that we can further develop the methods and teach them how we operate.”

This isn’t the first time that bitcoin has been shown be less private than many believe. A research paper published in 2014 showed that deanonymizing bitcoin transactions is neither hard nor expensive.

Photo: Riemann/Wikimedia Commons