Immigration Bureau and the Police Cyber Task Force searched two houses and two condominiums rented by the suspects and found they were being used as call centres to scam people, Roy said.
The suspects range in age from 21 to 44 and had previously operated a similar operation in China, before setting up shop in Chiang Mai, he said.
Police seized one computer, four tablets, 11 mobile phones, and seven landline phones, he said. The suspects were also charged for overstaying their visas.
Roy said the South Korean Embassy here had asked police to arrest the five for cheating people in Korea and said they had done the same in China.
The suspects admitted that they had called 30,000 phone numbers and swindled several people out of more than 50 million baht. They have been detained by Immigration Police.