A 18-year-old girl died at the Tonnau festival on Anglesey after suffering a cardiac arrest, an inquest has heard.
Lucy Ellen Halpin, from Bangor, Gwynedd, died on 11 July after being taken to hospital from the festival, which was held on the Carreglwyd estate in Llanfaethlu.
Coroner Kate Robertson said she had reason to suspect the cause of death was unnatural and a post-mortem examination was being carried out.
The Tonnau festival was cancelled following the incident, with organisers allowing emergency services to investigate.
Ribble Valley Brewery, who hosted the festival, has released a statement expressing their condolences to Lucy's family and friends.
A fundraiser has been set up to help with funeral costs, with tributes pouring in for the teenager who was 'exceptionally good at looking after customers' at her workplace, Breeze Hill Bar, Eatery and Hotel.