A boy was chased and attacked with a hammer as 20 teenagers clashed in a Cheltenham park on Monday.
He was taken to hospital for treatment and a 15-year-old boy was arrested in connection with the incident.
Police were called Benhall Park shortly after 7.30pm following reports that an altercation had taken place between a group of around 20 teenagers.
The victim has since been discharged from hospital and the arrested boy has been released under investigation.
Officers believe that this was an isolated incident however they are appealing for witnesses to the incident.
Anyone with information is asked to complete an online form quoting incident 493 of June 14 or calling 101.
Information can also be submitted anonymously by contacting the independent crime-fighting charity Crimestoppers on 0800 555 111 or through their online form.
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