David Cupples, 25, was found savagely beaten on Sunday in a tough area of Belfast where loyalist and republican areas join and he died of his injuries three days later.
He was found close to the Girdwood army base where he was a civilian worker.
Detectives think that he may have been attacked by a loyalist gang who assumed that he was a Catholic.
Mr Cupples, a Protestant from the east of the city, had been dropped off by a taxi some distance from the army camp because he did not want the driver to know where he worked and was attacked as he walked through a loyalist part of the run-down Cliftonpark area.
Sectarian attacks are commonplace in the area, which is one of the most dangerous and bitterly divided parts of the city. However, this was a particularly savage attack.
Det Supt Hugo Frew said: “David was the victim of a vicious assault which left him with severe head injuries. The injuries were so severe that we believe some sort of object was used in the attack. His family are totally devastated at what happened.
“A death at any time of year is hard to bear but at this time of year and in these horrendous circumstances, it is particularly tragic.
“David was a single man who was inoffensive and well-liked and respected by his colleagues in his place of work.”
He said he was sure that the fact that he worked at an army base was not the reason for the attack.