The 34-year-old victim sustained head injuries after he was assaulted in North Street, Brighton, around 3.59am on Saturday (December 21), and detectives are seeking to determine if this incident contributed to the man’s death.
He was found at an address in Albany Villas, Hove.
Police said the cause of death remains under investigation at this stage, and anyone with any information is urged to report it online or call 101, quoting Operation Curve.
Four suspects were located and arrested at Brighton railway station shortly after the assault occurred, and a possible fifth suspect remains outstanding.
Sussex Police said three 18-year-old men and a 19-year-old man, all from Crawley, arrested on suspicion of committing grievous bodily harm, have been released under investigation pending further enquiries.