Early this month, it was discovered that criminals had infected the 21 ATM computers with malware to dispense cash without authorisation.
Immigration police chief Pol Lt-General Natthorn Phrosunthorn Friday said his office – which assisted the investigation led by national police's senior adviser Pol General Panya Mamen – used security camera footage of suspects to compare with images of Eastern European visitors, mainly from Russia, Romania, Latvia and Estonia.
The aim was to narrow it down to men aged between 25 and 35.