Detectives from Melbourne Sexual Offences and Child Abuse Team are investigating a sexual assault which occurred in West Melbourne earlier this year.
Two women were waiting for a car ride service on Spencer Street about 1am on Sunday 26 January.
A man approached the women and sexually assaulted one of them before leaving the scene.
The offender is perceived to be Caucasian with a solid build and was wearing a white t-shirt.
Investigators have released an image and video of a man they believe may be able to assist with their enquiries.
Anyone who recognises the man or with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au