South Africa's Postbank lost R42 million (£3.5 million) to cybercriminals who hacked into its computer systems and withdrew the looted cash from ATMs over the New Year holiday period.
The crooks gained access to a Post Office employee's computer and used it to deposit cash into a number of bogus acccounts that were opened across the country late last year.
The cash was withdrawn from ATMs in Gauteng, Free State and KwaZulu-Natal over three days between 1-3 January.
The country's National Intelligence Agency has launched a high-level probe into the incident.
The bank told local newspapers that none of its customers were affected, but declined further comment.