600 computers used for mining bitcoin and other virtual currencies have been stolen from data centers in Reykjavik, Iceland in what authorities say is the biggest series of thefts that has ever taken place on the island nation. The media outlets of the country have dubbed the incident the “Big Bitcoin Heist.”

So far, 11 individuals were arrested, including a security guard. At the Reykjanes District Court, the judge ordered on Friday that two other people remain in custody.

The powerful processing machines, which have not yet been traced, are worth an approximate $2 million. But if the stolen hardware are used to mine bitcoins, the bandits could make huge earnings that could not be traced without ever needing to sell the stolen items.

“This is a grand theft on a scale unseen before,” noted the police commissioner on the southwestern Reykjanes peninsula, Olafur Helgi Kjartansson, where two of the robberies occured. “Everything points to this being a highly organized crime.”

Three of four burglaries happened in December and a fourth one occurred in January, but authorities did not release information about such news to the public earlier, hoping to trace and capture the perpetrators.

Bitcoin is digital currency that is unregulated by any bank or financial institution. Being incredibly volatile, its price has seen soaring highs and lows in just a day. The value of one bitcoin almost hit $20,000 in the last months of 2017, plunging again early this year. This Friday it was trading just below $11,000 USD.

Bitcoin and other cryptocurrencies depend on the blockchain which is made up out of public, distributed ledgers that track who was in possession of the coin. The bitcoin ledger is supplied with electrical power by miners that use their hardware’s computational energy to produce new bitcoins in return. To hardness such computational power usually equates to a high number of computers, and consequently a large amount of electricity.

That need for energy has resulted in people looking for ways of producing bitcoin more cheaply to come to Iceland. Because of this, cryptocurrency miners have been flooding into the island in past months to take advantage of the island state’s geothermal and hydroelectric power plants.

Police authorities tracking the stolen mining machines are keeping under surveillance all the electric consumption that is taking place in the country, hoping to catch the catch the culprits should they start using the hardware for mining operations, said an anonymous industry source.

A huge spike in energy usage might point to the location of the thieves and mining computers.

Authorities have urged local internet providers, electricians and storage space units to report any unusual activities that concern high amounts of electricity. The craze for bitcoin has lead to a series of incidents in which individuals have resorted to illegal means to procure the coin.