A man is in a critical condition in hospital after being found injured in a street in Worthing.
It's alleged he had been assaulted in nearby Longcroft Park just before 7.30pm on Easter Sunday.
Officers were called to Whitebeam Road and the man was treated at the scene by air ambulance staff before being taken to the Royal Sussex County Hospital in Brighton, where he remains in a life-threatening condition.
Police attended the scene and a short time later arrested four males in connection with the assault. They remain in custody at this time.
Officers say they are treating this as an isolated incident, but residents are told they can expect to see an increased police presence in the area while the investigation continues