A man suffered serious injuries as a result of the incident that occurred around 2.30am on High Street. The man remains in hospital receiving treatment for his injuries.
A 33-year old female was arrested as part of the investigation and has been released on police bail pending further enquiries.
Detective Constable Armstrong said: “We believe that a number of people may have been in the area socialising and I am appealing for anyone who may have been in the area of High Street or New Street in Donaghadee between 1.00am and 2.30am on Sunday. I am particularly keen to hear from anyone who may have seen or communicated with a male at a first floor window in High Street around this time.
“Anyone who has any information that can assist with the investigation is asked to contact detectives at Bangor PSNI Station on 101 quoting reference number 268 of 24/09/17.
“Or, if someone would prefer to provide information without giving their details they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.”