Two Taiwanese and Two Vietnamese nationals have been prosecuted for the mass disappearance in Taiwan of 152 tourists from Vietnam in December last year.

On March 5, the four were charged with forging travel documents, breaching the Employment Service Act and violating the Human Trafficking Prevention law, VN Express reported.

The four are prime suspects in the infamous case that saw 152 Vietnamese tourists go missing after arriving in Taiwan on tourist visas late last year.

Mai, a Vietnamese employee at a travel agency based in Hanoi, faked travel documents for 20 Vietnamese who were planning to find illegal work in Taiwan. She also arranged for them to join a tour group under special visas. The workers were reportedly charged US$1,000 to $3,000 per person.

She then led the tour group to Kaohsiung on December 21 after getting electronic visas for them. Another person had already been taken to Taichung six days earlier.

Her Taiwanese husband, Hsiao, was charged with harboring two Vietnamese citizens in their home for days, as well as getting another person with work as a delivery man in the city of Taoyuan.

A Taiwanese local and a Vietnamese citizen were charged with bringing 33 Vietnamese nationals into Taiwan after charging them US$1,000 to $2,500 each. Twenty-seven other suspects were also being tracked down by authorities in Taiwan.

The tourists reportedly applied for e-visas via the Kuan Hung visa scheme that was launched in 2015. Under the scheme, visitors from Vietnam, Myanmar, Cambodia, Laos, India and Indonesia enjoyed visa applications free of charge.

After the mass disappearances in December, the Taiwanese government suspended the program for Vietnamese nationals. As of February 19, 56 of the missing 152 tourists were still unaccounted for.