Four Korean teenagers allegedly involved in a case of group assault against a Vietnamese worker in Pocheon, Gyeonggi Province were transferred to the prosecution and the court, police said Wednesday.

Pocheon Police Station said it has referred the four teenagers to the prosecution and the juvenile department of the family court, respectively, on three charges, including joint principal offense, unlawful restraint and extortion, on Tuesday.

The police have accused the teens of assaulting a Vietnamese national in his 30s on a road in Naechon-myeon, Pocheon on July 1, and attempting to rob him.

The teens, who were on a motorcycle, reportedly saw that the man's motorcycle, which was passing by, had no license plate. Driving next to him, they told him to stop and then asked whether he had a wallet. They then threatened him, saying that they would report him to the authorities as an illegal migrant.

At first the teenagers claimed that the man had assaulted them, and so both parties were at first charged with assault, but after police examined closed-circuit TV footage, they discovered the teens had perpetrated the assault unilaterally.

The teens kicked the man in the stomach and dragged him across the road. The assault lasted for about an hour until the police arrived on the scene, according to local reports.

The police sent one of the teenagers -- the main culprit -- to the prosecution, and the other three to the juvenile department of the family court, respectively.

Juvenile trials are held in private and no criminal record is left. If found guilty, the youths will be sent to juvenile detention centers or be subject to probationary measures such as education in custody or community service. If, as a result of an investigation or trial, the juvenile department finds evidence of criminal acts that deserve imprisonment without prison labor or heavier punishments, and if the juvenile department deems it necessary in light of the accused's motive and the nature of the crime committed to impose criminal punishment upon the juvenile concerned, it can transfer the case to the prosecution.

Meanwhile, the victim was found to be residing illegally in Korea. He is expected to receive a short-term visa designated for foreign victims of crimes.