Police investigating the death of Lee Molineau are questioning a 22-year-old woman.
She was arrested shortly before 1am on Thursday (August 1) at an address in Langney Road and taken in to be interviewed on suspicion of murder.
Lee Molineau, 46, of no fixed address, died at Hurstwood Park neurological unit in Haywards Heath on Tuesday (July 30) after he was assaulted six days earlier.
He had suffered a serious head injury following an argument between him and two women in Seaside Road during which an unknown man intervened and assaulted the victim.
That man, who then ran off, is described as white, in his early 30s, of tanned complexion, 6ft, and of stocky athletic build with short cropped hair. He was wearing a white T-shirt, blue jeans and white footwear.
Detective Chief Inspector Ian Pollard, of the Surrey and Sussex Major Crime Team, said, “There has been a very good response from the community following Lee’s death and as a result of that a female was arrested in the early hours of the morning.
“We also carried out a search of another address in the early hours in Eastbourne as part of our search for a male suspect but he remains outstanding.”
One woman has already been charged with an offence in connection with the incident.
Ruby Heard, 25, of Lexden Drive, Seaford, will appear at Lewes Crown Court on 23 August charged with causing grievous bodily harm with intent.
Anyone with information about the investigation should call 101 quoting Operation Haldon or the independent charity Crimestoppers anonymously on 0800 555111.