Police have arrested eight men in connection with a £1.3m 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 Swiss Cottage branch in north London 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 on 5 April.

The modus operandi appears almost identical to an alleged plot targeting a Santander branch in Surrey Quays, south-east London, which resulted in 12 men being arrested last week. The plot was foiled by the Metropolitan police.

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 the arrests last week.

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

The gang used a central London property as a control centre, police said.

Officers recovered property including cash, jewellery, drugs, thousands of credit cards and personal data in raids on addresses in Westminster, Newham, Camden, Brent and Essex. The arrests came after a lengthy intelligence operation by the PCeU, working with Barclays. 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 costs about £20 and lets computer users work remotely. Police said Barclays had recovered a significant amount of the stolen money. 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 others have been bailed to a date in mid-November pending further enquiries.

At the time of the Santander arrests, Raymond described it as "the most significant case of this kind that we have come across".