Police are appealing for information about a suspected incident which left a 25-year-old man unconscious for four days.
The man was discovered lying on the floor of Woodfield Social Club car park, in Woodfield Road, Balby, at about 12.30am on Sunday August 18.
He had sustained serious head injuries and was taken to hospital where he underwent treatment for more than a week. Due to the nature of his injuries, the man has no recollection of what happened.
Detective Constable Keith Black said: “It is unclear exactly how he came to sustain such serious injuries as he has no recollection of an incident, the last thing he remembers is walking across the club’s car park.
“There were several people at the club that night and we have not yet spoken to everyone who was present. I’m appealing to anyone who was at the venue to contact officers and also to the person who found the victim, and called the ambulance service, to get in touch.
“We are trying to establish exactly what happened to the victim and need the public’s help in doing this.”
Anyone with information is asked to call South Yorkshire Police on 101, quoting incident number 18 August, or Crimestoppers anonymously on 0800 555 111.