Ten Vietnamese nationals staying in South Korea illegally were arrested earlier this week for allegedly purchasing forged alien registration certificates.

The 10 Vietnamese are being investigated under charges of forging official documents as well as violating the Immigration Control Act, VN Express reported. A Chinese broker had been asked by the group to forge registration certificates for the illegals in a bid to avoid being detected by local police.

The Vietnamese allegedly paid US$442 to $531 per document.

From late February to early March, officers at Incheon International Airport in Seoul found 13 fake certificates sent via international express mail from China. Using the information on the mail, immigration officers started a manhunt for a 20-year-old Vietnamese man who was staying illegally in Seoul.

Nine more Vietnamese nationals were later apprehended in Seoul as well as other provinces. According to police, the Vietnamese had been overstaying in the country for years.

Authorities were on the lookout for three more suspects.