Jersey Police are asking parents to check whether their children have seen video footage of a fight involving forty teenagers.
At least one boy aged 15, and an adult who tried to intervene, were assaulted.
The brawl happened in Howard Davis Park just after 4pm on Friday 14th June.
Police say one of the boys seen leaving had a 'sizeable' amount of blood on the back of white school shirt.
Nobody received medical treatment.
All those involved are thought to have been aged about 15.
The force says it is aware that footage of the fight was taken on mobile phones and has since been circulated on Snapchat.
It says parents should speak to their children about whether they are aware of it, and any information should be reported to police or Crimestoppers.
"Anyone who may have seen this or who has any information is asked to contact police on 612612 or the independent charity Crimestoppers anonymously on 0800 555 111 or via their Anonymous Online Form at Crimestoppers-uk.org"
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