Police in the central Vietnamese province of Phu Yen on Monday arrested four teenagers who randomly attacked people on the street.
The assailants killed one and injured many others earlier this month.
Nguyen Tuong Nghiem, 16, and three others Vo Quoc Tri, Nguyen Kim Dien, and Phan Ngoc De, 17, attacked 12 people in a half hour on the night of August 12.
One of the victims Nguyen Thanh Chung, 32, was hit on the head with cudgels and died at hospital with brain injuries.
The boys also threw rocks at 14-year-old Trinh Van Giang, who was then rushed to hospital for brain surgery.
Several other victims are still being treated at the hospital, police said.
The attackers, who had traveled on two motorbikes with the lights turned off, told the police that they were drunk and could not control themselves.