A Polish man was attacked with a piece of wood in Bognor Regis on Tuesday (October 9).
Police are looking for witnesses to the incident which happened in a waste area next to Clifton Court in Clifton Road at about 9.15pm.
It is believed he was attacked by a group of Polish people.
The victim is in a medically induced coma with head injuries in hospital in Southampton.
Detective sergeant Sally Arbuckle said: “Were you in the area at the time and see or hear anything? Please contact police on 101 quoting serial 1600 of 9/10. Or the independent charity Crimestoppers anonymously on 0800 555 111.”