In what has been dubbed the “big bitcoin heist,” 600 computers used to mine cryptocurrencies have been stolen in Iceland. The powerful computers are worth almost $2 million.

The computers were stolen from data centers across the country. Police said it’s the biggest series of robberies to happen in Iceland, and it’s believed to be connected to organized crime, Iceland Monitor reports.

“This is a grand theft on a scale unseen before,” Reykjanes police chief Olafur Helgi Kjartansson said, AP reports. “Everything points to this being a highly organized crime.”

Where on Earth can we find the cheapest place to start mining bitcoin? https://t.co/zpeGorDMOR — RT (@RT_com) March 3, 2018

The thefts took place in Reykjanes and Borgarbyggð, Visir reports. Three of the thefts happened in December and one in January. Police decided not to announce the crimes in an effort to find the thieves.

Advania Data Manager provided images from its security cameras at its data center in Reykjanesbær, which helped police, Visir reports. Eleven people have been arrested in connection with the crimes, including one security guard. On Friday, a Reykjanes District Court ruled two of the people should remain in custody.

Cryptocurrency is created by using powerful computers to solve complex mathematical problems. Mining cryptocurrencies requires a lot of computing power, so authorities are monitoring electricity consumption in the country in an effort to catch the thieves. Police have asked internet providers, electricians and storage space owners to report any unusual requests for additional power.

Iceland has become an attractive place for mining bitcoin due to its renewable geothermal and hydroelectric power plants, and cool temperatures, favorable for preventing mining computers from overheating.

Crypto mining rig thefts are likely to rise in step with the value of the currency. When a new bitcoin block is mined, it’s worth a 12.52 Bitcoin reward, News BTC reports, which is worth about $137,500 at time of writing. In Malaysia, nine people were arrested last week after 58 mining rigs were stolen, News BTC reports.

Think your friends would be interested? Share this story!