A teenager remained critically injured after he was stabbed following a large gathering in the grounds of a house in rural Sussex, police said.
The 17-year-old was stabbed in the chest in the early hours of Sunday morning in a house in Marches Road, Warnham, West Sussex.
A 16-year-old was arrested on suspicion of attempted murder and remained in police custody.
The incident happened as "many young people" gathered at the property for an event.
Sussex police called it an “isolated incident” and said the condition of the teenager remained critical.
The police are appealing for witnesses, including parents and other young people to provide information about the stabbing.
Chief superintendent Jo Banks said: “We are urging witnesses and anyone with information to come forward.
“We understand that there were many young people in attendance at this address at the time who will know important information to help the investigation.
“In particular we would also ask parents and carers of those who attended to speak with their children and to contact us with information.
“This is a fast-moving and complex investigation.
“Officers will be working in partnership with local schools and there will also be an increased police presence in the area in order to provide reassurance.
“We believe this was an isolated incident that does not pose a wider threat to the community.”
Pictures of the crime scene showed white tents covered with bunting, cordoned off by police tape in the midst of a field.
