Police in Dunedin are speaking to a 25-year-old man about the death of a man at a bar in the Octagon.
They were called to the Craft Bar about 1.45am on Sunday after an assault complaint.
A 35-year-old-man was found unconscious in the toilet area and could not be revived.
Inspector Jason Guthrie says the police have begun a homicide investigation and one of the 60 people who were in the bar at the time is helping them with their inquiries. He says the incident is tragic.
"It certainly is concerning to us that this type of incident has happened in Dunedin. Tragically someone has lost their life and this affects not only the victim and the offender but also a far wider circle of friends, associates and families."
Mr Guthrie says the name of the dead man is not being released until next of kin are told.