A 14-year-old girl was left with a head injury after being attacked by a group in Keynsham.
The assault happened in St Clements Road on 19 September at around 2.45pm.
Police say she was attacked by a gang of five people, which included two boys on electric scooters.
Officers are now appealing for witnesses to come forward.
A spokesperson from Avon and Somerset Police said: "We’re appealing for a key witness to come forward following an assault on a 14-year-old girl in Keynsham.
"While giving her official statement, the victim mentioned that a woman with a small child may have witnessed or walked past the incident while it was happening – and we would very much like to identify this witness."
Police hope the witness herself, or anybody else who have seen information, to call police on 101 and give the call handler the reference number 5221218273.