A Sydney 14-year-old boy has been tied to a tree and had his mullet hair cut off in what is believed to be a school retaliation.
Police said the boy was riding his BMX bike through Tandarra Reserve at Shalvey, in Sydney's west, when he was ambushed by four males about 4.30pm (local time) on Tuesday.
"He was approached by one person who threatened him and that young person has then punched him and knocked him off the BMX bike he was riding," Mt Druitt Local Area Command duty officer Chief Inspector Wayne McMahon told AAP.
"He's got on his bike again to try to make good his escape when three other young persons have started to come across and they've also knocked him off his bike."
The boy was then tied to a tree with a piece of cord while his attackers kicked and punched him.
They also cut off the boy's mullet hairstyle and stole the sim card from his phone.
The assault only ended when a friend of the victim who lives nearby ran into the park and yelled out for the group to stop.
Mr McMahon said the assault may have been motivated by a dispute at school which "followed on to out-of-school hours".
Police said the boy was taken to Westmead Hospital in a stable condition with severe facial injuries.
- AAP