Two men are still being questioned over the murder of Newtownards man Richard Miskelly.
The 24-year-old died after an assault at a house on Bangor Road in the town at about 05:30 GMT on Sunday.
Mr Miskelly was found lying on the road. He was treated by ambulance staff, but died at the scene a short time later.
Two 19-year-olds were arrested on suspicion of his murder and remain in custody.
Police said a post mortem examination would be carried out to help determine what caused his death.
The officer leading the investigation, Det Ch Insp Justyn Galloway, said the incident had resulted in the "tragic death" of a young man.
"I would like to thank the local community for their support in this investigation," he said.
"I would appeal to anyone who has any information that they think could help but hasn't yet contacted us to get in touch with detectives."