Transit Crime Investigation Unit detectives are hoping to identify a man following a sexual assault on a train from Thornbury this month, Victoria Police say.
Police have been told a woman boarded a city bound train at Thornbury Railway Station about 9.35am on 16 May.
During the commute the woman has been repeatedly sexually assaulted by an unknown man.
The 49-year-old woman moved away from him several times but he continually followed her.
She got off the train at Flagstaff Station and he continued to follow her and engage in conversation.
She alerted train station staff and the offender left the station.
The man is perceived to be of Islander or Asian appearance, 20-25-years-old, approximately 160cm tall slim build and a thin moustache.
He was wearing a navy New York Yankees baseball cap, navy baseball style jacket with white sleeves and beige pants.
Police have released images of a man they believe may be able to assist with their enquiries.
Anyone with information is urged to contact Crime Stoppers.
