A Bulgarian tourist believed to be part of a foreign gang was arrested for allegedly tampering with ATMs in Thailand.

Ivan Valchev, 50, reportedly helped install malware-laden data cables into the machines in Nonthaburi on the outskirts of Bangkok. The software, called Jackpot, caused the ATMs to dispense more money than the amount entered on the keypad.

The suspected gangster was detained at a rented house on May 27. Officers seized from him several stolen transmission cables and computer equipment believed to have been used in the thefts.

Police said the arrest stemmed from a complaint lodged by a Thai bank in March. They reviewed security footage in the vicinity of the hacked ATM and found suspicious individuals dressed as mechanics arriving in the area.

The uniformed personnel carried a toolbox containing a 'master key' which they used to open the machine. Investigations found that the gang had targeted a total of 13 ATMs across the province.

Police Lieutenant General Trairong Phiewpan, commissioner of the Cyber Crime Investigation Bureau, said Ivan will be charged with 'theft at night using a vehicle, intercepting computer data, causing damage to computer data, disrupting a computer system, causing disruption to a computer system related to economic security, fraudulently committing acts against a computer system, and unlawfully accessing protected computer data'.

He added: ‘The suspect denied all charges, and we handed him over to the inquiry officer for legal action. Currently, we are tracking down those who collaborated with him and investigating others related to the operation.'

Ivan has denied all charges.