A 21-year-old woman was seriously assaulted in Edinburgh's Canongate Kirk area as the city hosted thousands of Hogmanay revellers.
The victim was attacked sometime between midnight and 2.30am yesterday and police are keen to speak to anyone in the area at that time.
Officers have released an updated description of the suspect, who is white and in his late teens or early 20s.
He is of slim to medium build and wore a "distinctive" furry head-band.
Detective Inspector Bobby Deas said: "Through ongoing inquiries we have obtained a more consistent description of the suspect and detectives are now progressing with the investigation to trace this male.
"Anyone who believes they can help identify him is asked to come forward.
"Similarly, we continue to urge those who remember seeing anything suspicious in or around the Canongate in the early hours of New Year's Day to get in touch."
Police Scotland are also investigating a sexual attack in Aviemore in the Highlands in the early hours of New Year's Day.
A woman was assaulted at around 1.30am in the area known as the tunnel, near the Vault nightclub.