Four people have been arrested by detectives investigating the suspected theft of 1 million pounds ($1.6 million) from two U.K. banks, police in London said Wednesday.
Metropolitan Police said search warrants executed at two addresses on Tuesday as part of the investigation turned up 80,000 pounds ($131,000) in cash, luxury goods and a suspected live hand grenade. Detectives also seized a Range Rover and computers.
Cybercrime detectives launched the operation after being alerted that “a number” of bank customers had unknowingly downloaded malware by opening emails allegedly from their banks. Some 1 million pounds was siphoned from accounts, transferred to be laundered and then withdrawn as cash.
Detectives arrested two 31-year-old men, a 27-year-old woman and a 24-year-old woman on suspicion of conspiracy to defraud, launder money and possessing an explosive. The men are in custody and the women have been released on bail.
Police said the investigation was carried out with the assistance of several banks, but did not specify which ones.
The arrests are just the latest in a string of cyberthefts and suspected cyberthefts involving banks in the U.K.
In September, four men were charged in the U.K. in connection with the theft of 1.3 million pounds from a Barclays Bank branch by installing a device on the bank’s computer system which enabled the cybertheft.
Those charges followed a failed attempt to use similar technology to rob another bank, Santander. Four others have been charged in that case.