Barry Solomon, 42, was discovered in a house in Kemble Square in Downhill, Sunderland on Saturday night.
Three youths arrested in connection with the death have been released on bail. A 39-year-old woman who was also arrested has been released "under investigation", without bail.
A cordon is in place at the property. Officers have appealed for witnesses.
The death of a man who was found with "significant injuries" is being treated as murder, Northumbria police said.