Investigative sources in Japan say a 16-year-old boy, who is believed to have been forced to work for a scam group in Myanmar, was taken to the country after applying for an overseas job advertisement which later proved to be a "shady job" offer.

A number of Japanese nationals, who were likely to have been forced to work at scam centers in Myanmar, have been placed under protective custody by authorities in Thailand in January and February. The high school boy from Aichi Prefecture, central Japan, was among those in custody.

The sources said the boy signed up online for an overseas job, which was in fact a shady part-time job. They said he went to Thailand in December last year, and then believed to be taken to Myanmar.

Japanese police had been searching for the boy at the request of his family.

Thai authorities suspect the boy was involved in making fraudulent phone calls.

The sources said the boy has already returned to Japan. Police plan to question the boy.