Transit Crime Investigation Unit detectives are investigating a sexual assault on a Pakenham bound train last year.
Investigators were told a 21-year-old woman was seated on an outbound train on 9 October about 4.40pm.
A man sat next to the victim before he touched her inappropriately on her upper thigh.
This incident is believed to have occurred while the train was in transit between Caulfield and Dandenong railway stations.
Following the incident, the man got off the train at Dandenong train station.
Detectives have released an image of a man who they believe may be able to assist them with their enquiries.
Anyone who witnessed the incident or with any information as to the identity of the man is urged to contact Crime Stoppers on 1800 333 000 or to submit confidential report at www.crimestoppersvic.com.au
