A video of a high school student beating up a security guard in his 60s has sparked public outrage here, despite the police closing the case when the victim expressed his wish not to punish his attacker.

In the video that went viral through the social media, the teen was filmed launching series of brutal attacks against the man on Friday, as a female voice was heard laughing at the scene.

The assault occurred at a commercial complex in Dasan-dong in Namyangju City, Gyeonggi Province.

Local police said officers were dispatched to the scene, but the victim refused to seek charges. He told the police that the teenager apologized to him after the incident, and insisted that he did not want the boy to be punished.

It is unclear what the exact situation was, but the teenager and his friends reportedly created a disturbance in the building and the security guard came and scolded them

"He (the high school student) did beat an adult, but he apologized and I forgave him. I was in the wrong, too. I could've used nicer words," the victim told local media.

Inflicting bodily injury on another can be punished by up to two years in prison or 5 million won ($3,800) in fine, and those aged between 14 and 18 are subject to punishment stipulated by the Juvenile Act.

But the South Korean law prohibits punishment of certain crimes -- including assault -- if the victim says they do not want the offender to be punished.

After the video was uploaded, some viewers worked out the location of the assault, while others revealed what they claimed to be the attacker's name, residence and where he went to school.