A woman and three teenagers are being questioned over the gang-bashing of a 14-year-old whose mullet was cut off.
The victim told police he was riding his BMX bike through Tandarra Reserve at Shalvey, in Sydney's west, after school on Tuesday when he was ambushed by four males.
He sustained severe facial injuries in the attack.
Police believed he had been knocked off his bike, then tied to a tree with a piece of cord while his attackers kicked and punched him, cut off his mullet hairstyle and stole the SIM card from his phone.
On Thursday evening a woman, a 14-year-old girl and two 16-year-old boys were detained in Shalvey.
A police spokeswoman told AAP they were assisting Mount Druitt detectives with inquiries.
