Police have arrested eight men in connection with a £1.3 million theft by a gang who remotely took control of the computer system of a Barclays bank branch.

A man posing as an IT engineer gained access to the branch on 4 April, fitting a keyboard video mouse (KVM) device, which enabled the gang to remotely transfer funds to bank accounts under its control. Barclays reported the theft at its Swiss Cottage branch in north London on 5 April.

The modus operandi of the theft appears almost identical to a plot targeting a Santander branch in Surrey Quays, southeast London, which resulted in 12 men being arrested last week. In that case a bogus engineer also fitted a KVM device to a computer at the branch but the London Metropolitan police — known as the Met — foiled the plot as the men were about to be in a position to execute the operation.

Scotland Yard said links between the two plots were being investigated but none of those arrested on Thursday and Friday in connection with the Barclays theft were among last week’s arrests.

The eight men are being questioned at London police stations on suspicion of conspiracy to steal from Barclays and conspiracy to defraud U.K. banks.

Detective Inspector Mark Raymond of the Met’s central e-crime unit (PCeU) said: “These arrests were achieved working in partnership with the virtual taskforce, a unique information sharing cyber collaboration between the PCeU and the U.K. banking sector.

“Those responsible for this offence are significant players within a sophisticated and determined organised criminal network, who used considerable technical abilities and traditional criminal know-how to infiltrate and exploit secure banking systems.” One central London property was deployed as a control centre for the gang to work from, police said.

Officers recovered property including cash, jewellery, drugs, thousands of credit cards and personal data in raids on addresses in Westminster, Newham, Camden and Brent, all in London, and Essex.

The arrests came after a long-term intelligence operation by the PCeU, working with Barclays. After the thefts were reported to Scotland Yard, an investigation was launched and a search of the Swiss Cottage branch uncovered a KVM switch attached to a 3G router connected to one of the branch computers. A KVM switch is a hardware device, which can be purchased for about £20 that allows users to work remotely on their computer systems.

Police said Barclays had recovered a significant amount. Alex Grant, managing director of fraud prevention at the bank, said: “We identified the fraud and acted swiftly to recover funds on the same day. We can confirm that no customers suffered financial loss as a result of this action.” Four people have been charged with conspiracy to steal in connection with the attempted theft from Santander. Eight other people have been bailed to a date in mid-November pending further enquiries. At the time of the Santander arrests, Mr. Raymond described it as “the most significant case of this kind that we have come across”. — © Guardian Newspapers Limited, 2013