Authorities in Vietnam have arrested five more people who they claim were connected to the disappearance of 152 Vietnamese tourists in Taiwan in late 2018.

On May 6, the Ministry of Public Security of Vietnam announced a woman and four men were being investigated under the charges of “organizing and/or coercing other people to flee abroad,” VN Express reported. If found guilty, they could be jailed for up to 20 years.

The woman, Nguyen Thi Thanh Ha, 35, will be held in custody while the investigation is ongoing, along with three men – Tran Van Danh, 30, Vu Nhat Tuan, 49, and Nguyen Xuan Hung, 41.

Nguyen Lam Sy, 35, was placed under house arrest.

According to official statistics, 56 of the 152 disappeared tourists from Vietnam were still reported missing in Taiwan as of February 19. Some of those who turned themselves in or were traced by police confessed they were hoping to find illegal work in Taiwan.

The tourists who had gone missing had entered the country under the Kuan Hung visa – which requires no visa fees for visitors from Vietnam, Indonesia, Cambodia, India and Laos. The initiative was a part of Taiwan’s policies to strengthen ties with those nations.

However, after the mass disappearance, Taiwan suspended the program with Vietnam.