Transit Crime Investigation Unit detectives are investigating a sexual assault that occurred on a route 96-tram last month.
Investigators have been told a 14-year-old girl was on a tram heading from Southern Cross Station to St Kilda about 10.30am on Sunday 2 February.
An unknown man approached the girl from behind and sexually assaulted her before getting off the tram in St Kilda.
Investigators have released an image of a man they believe may be able to assist with their enquiries.
The man is perceived to be of Indian Sub-Continental appearance, aged 25-30-years-old, approximately 180cm tall, and has a medium build.
He was wearing a black t-shirt, blue jeans, white runners and has distinctive tribal style tattoos on his upper right arm and forearm.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au