The General Department of Immigration (GDI) is questioning 49 Vietnamese nationals who were working illegally in Koh Kong province to build a case and send them back to Vietnam, its Department of Investigation and Procedure director Kem Sarin said on Thursday.

GDI forces and provincial authorities found the 49 workers, including three women, staying illegally on 18 sand dredgers in Sre Ambel district’s Bak Angroth and Cher Tal Pneas villages.

After investigating, authorities found that they did not have legal documents or passports.

“Legally, we have to send them back from Cambodia because it is illegal for them to stay and work here,” Sarin said.

Provincial police chief Sam Khitvean said on Thursday that provincial police officers worked in collaboration with the GDI to detain the workers.

Khitvean said the responsibility of applying the law resides with the GDI.

He said one or two Vietnamese nationals had been sent back to Vietnam in the past for working illegally in Cambodia.

The next legal step, which involves the owners of sand-dredging businesses, is the department’s responsibility, he said.