Ho Chi Minh City prosecutors Thursday filed charges against a supermarket security guard for beating up a high-school student seven months ago.

Phan Ba Dung, 23, has been indicted for "intentionally causing bodily harm" to 18-year-old Tran Hoang An of Nam Ky Khoi Nghia High School in District 11.

On May 30 An and 40 classmates attended a farewell party in the Lotte Mart building in District 11, and after the party went to the basement to get their motorbikes.

An found his helmet missing and picked a fight with Hoang The Vinh, a security guard, almost attacking him.

Dung rushed to the scene to help his colleague, and hit An on the forehead with a walkie-talkie.

The other students and more security guards, including Vinh and Dao Cong Nguyen, joined the fight which only stopped after the police showed up.

An was hospitalized with multiple injuries, while some other students sustained minor injuries.

An was later exempt from taking the high-school graduation exam.

The police said Vinh and Nguyen's acts were not serious enough to press criminal charges against them, so they were merely fined