Detectives form the Transit Crime Investigation Unit are hoping to identify a man after he engaged in a sexual act on a tram in Caulfield South last month.
Investigators have been told a 15-year-old girl was on board the Hawthorn Road tram about 3.20pm on 24 June.
The girl was seated on the tram when she turned around and observed a man staring at her and masturbating.
The quick-thinking teen took a photo of the man before he got off at Sycamore Street.
Investigators have released an image of a man they believe may be able to assist with their enquiries.
The man is perceived to be Aboriginal or Torres Strait Islander in appearance, aged in his 50s with grey hair and a grey beard.
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
