Three men have been arrested on suspicion of manslaughter of a 20-year-old woman in Ballynahinch on Thursday.
Police received a report around 8.30pm on Thursday evening that a woman was found collapsed within a unit of flats on Dromore Street in the Co Down town.
It was later confirmed that the woman had died.
The cause of death is not yet know and police said a post-mortem examination will take place in due course to determine it.
The three men - two aged 26 and one aged 30 - remain in custody.