"It was just a young girl walking home, minding her own business and these people have decided it might be fun to attack this lone female, which suggests something of their character to pick on a young girl like that," he said.
Mr Milne said the girl had seen the teens hanging around near the hockey field's grandstand building a minute or so earlier and at that stage there were two other young men with them.
"She thought that two of the group were walking away then, so there might have initially been at least five of them in the group before these three attacked her," he said.
"She then heard some voices closer, with swearing and stuff, and she started to run as she realised they were after her. One of the group grabbed her by the hair and got two punches into her before she managed to escape."
The girl fled across the field and along Raihara St. She could give only a brief description of the attackers. One was wearing a light coloured long sleeve top and a beanie and the other two were wearing caps. One was riding a BMX bike.
"Most people may not think they have any information, but anything can be relevant, no matter how small they may think it is the colour of the BMX bike, or descriptions or colours of their clothing - anything that might help," said Mr Milne.
