Indian engineer Stephen Wesley was puzzled when he was asked to take a typing test during an interview for a graphic design job in Thailand — but put it out of his mind when he got the role.

Hours after landing in Bangkok to start work in July, Wesley and seven other new recruits were instead ferried over the border into Myanmar where their phones and passports were taken, and they were put to work on online cryptocurrency scams.

"I spent up to 18 hours a day researching, typing messages, chatting with people on social media platforms, gaining their trust and encouraging them to invest in cryptocurrency," said Wesley, 29, in a telephone interview.