Eight people have been arrested in New York in connection to an ATM hacking scheme that resulted in the theft of $45 million over the course of a few hours. According to the US Immigrations and Customs Enforcement division of the Department of Homeland Security, the suspects hacked into the computer systems of banking institutions to steal the money in two coordinated attacks.

Though the arrests were made in Yonkers, NY, officials say the suspects are part of an international crime ring that utilizes hacking techniques to steal money electronically. The attacks, committed in December 2012 and February of this year, involved ATM withdrawals in 20 different countries. One of the attacks performed more than 36,000 transactions over the course of 10 hours. The thieves then laundered the money through purchases of luxury goods, such as jewelry and sports cars.

More than 36,000 transactions were performed over the course of 10 hours

Prosecutors have dubbed the attacks "Unlimited Operation," and U.S. Attorney Loretta E. Lynch, Eastern District of New York says that "the organization worked its way from the computer systems of international corporations to the streets of New York City, with the defendants fanning out across Manhattan to steal millions of dollars from hundreds of ATMs in a matter of hours." She added, "this was indeed the largest theft of this type that we have yet seen." Prosecutors have also described the attack as a "criminal flash mob," thanks to its coordinated fashion.

No individual accounts were hacked into

Despite the large amount of money stolen, individual accounts were not targeted in the scheme. Instead, the hackers accessed the systems of debit card processors and greatly increased the value of specific prepaid debit cards, before withdrawing the funds from ATMs. The thieves would then coordinate their worldwide team to perform the ATM transactions in as little time as possible. Speaking to The Wall Street Journal, Lynch said that prosecutors were investigating specific individuals in Europe and Asia to find out the ringleaders of the crime ring.

Authorities did not say how they became aware of the operation or what tipped them off to arrest these specific suspects, but they did have surveillance camera footage of some of the ATM withdrawals taking place. The defendants face maximum sentences of 120 months in federal prison for each of the four counts of money laundering, as well as up to 90 months on the conspiracy to commit access device fraud charge, if they are convicted.