An 18-year-old died in hospital in Port Elizabeth, after he was stabbed at a music festival, Eastern Cape police said on Tuesday.
Lt-Col Priscilla Naidu identified the teenager as Brenden Claasen.
She said Claasen was with a group of friends at a festival in Uitenhage on Sunday, when someone threw an empty bottle from behind. The bottle hit a woman in the group.
"It is alleged that some people from the group chased after the alleged culprits while the others remained [behind]," she said.
A fight then broke out between the remaining friends and a new group of people. When the crowd dispersed Claasen and two other people were lying on the ground. All three appeared to have been stabbed.
Claasen died at Livingstone Hospital in Port Elizabeth on Monday.