Police have arrested eight men, including the alleged "Mr. Big" of British cybercrime, after robbers took remote control of a bank's computers to siphon off £1.3 million ($2 million).
The police linked the theft at Barclays(BCS) to another attempt to steal money from a Santander(SAN) branch in London, which led to the arrest of 12 men last week.
"The size and sophistication of the operation has shocked us and we're actually having to draft in more resources to deal with the amount of evidence that we've recovered," said detective superintendent Terry Wilson.
"This was a highly-organized criminal network," said Wilson. "All criminal networks have a head and we very much believe we have now apprehended our 'Mr Big' as part of this operation."
Police made the arrests linked to the Barclays plot on Thursday and Friday, and traced the fraudsters' "control center" to a home in central London.
They are still in the process of seizing property, cash, jewelry, drugs, thousands of credit cards and personal data in relation to the case. The eight men were arrested on suspicion of stealing and defrauding banks.
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Of the 12 men arrested last week, four were charged with conspiracy to steal, while the others were bailed but face further investigation.
Alex Grant from Barclays' fraud prevention unit said the bank was able to recover the money on the same day the theft was detected, meaning no customers suffered losses.