An attack on a 40-year-old homeless man in West Sussex is being treated as attempted murder, police have said.
The victim was assaulted early on Tuesday morning while he was asleep in a bus stop on the A259 in Fishbourne.
He was found by a member of the public with severe head injuries and is still in a critical condition in Southampton General Hospital.
Two 18-year-old men and two 17-year-old youths have been arrested and are helping police with their inquiries.
Det Insp Nigel Brown, who is leading the investigation, said: "This was a serious, unprovoked attack and we are appealing for anyone who may have witnessed it, or who may have information to come forward."