Sexual Crimes Squad detectives are appealing for public assistance after an 18-year-old woman was sexually assaulted in Narre Warren on 17 February.
Investigators have been told a woman was out with friends at a licensed premise on Princes Highway when she left about 2.30am.
She was walking along the Princes Highway and crossed Webb Street when she was approached by an unknown person or persons about 2.40am.
The victim was grabbed and dragged to the ground before she was sexually assaulted, police say.
Detectives wish to speak to any witnesses in the area at the time or anyone that may have seen the woman being pulled to the ground.
Anyone with any information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au