Metropolitan Police have arrested eight men in connection with a £1.3m robbery that allegedly involved taking control of a Barclays Bank branch computer.
A hardware device that allows workers to access their computer systems remotely, a KVM switch, was found attached to a 3G router on the computer in the branch at Swiss cottage in north London. KVM switches can be bought for as little as £10 over the internet.
Police said that this method of tapping into personal data was a "rapidly evolving" field of cybercrime.
"This new methodology demonstrates the rapidly evolving nature of low-risk, high-financial yield cyber-enabled crime," said the Metropolitan Police.
The suspects, aged between 24 and 47, were in police custody facing fraud and theft conspiracy charges. Police said they had posed as engineers to attach the hardware device to the router.
A number of London addresses in Westminster, Newham, Camden, Brent, and Essex were being searched by detectives. One property was described as the "control" centre.
Police have seized thousands of credit cards and personal data, as well as, cash, jewellery, and drugs. They said they had recovered a "significant amount" of stolen cash.
DI Mark Raymond of the Met's Central e-Crime Unit said : "Those responsible for this offence are significant players within a sophisticated and determined organised criminal network, who used considerable technical abilities and traditional criminal knowhow to infiltrate and exploit secure banking systems."