A woman was sexually assaulted in the Merrion Avenue area of Newcastle in the early hours of Sunday.
Detectives are currently investigating the incident which is believed to have occurred around 2:30am.
Anyone with any information is asked to contact detectives in Strandtown Station on 101.
Alternatively, information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.