Police are investigating after a woman and a teenage girl were sexually assaulted on public transport in two separate incidents believed to be linked, Victoria Police say.
The 21-year-old victim was travelling into the city on a train from Murrumbeena on Sunday 20 November 2016 about 5pm.
An unknown man boarded the train at Carnegie Railway Station and sat next to the victim before sexually assaulting her between Carnegie and South Yarra railway stations.
Police believe the offender got off the train at Flinders Street Station.
Detectives believe the same man followed a 14¬-year-old girl from the Dandenong Railway Station on Thursday 16 February about 3.50pm.
The offender boarded the same Route 845 bus as the victim, sitting next to her before sexually assaulting her.
He is believed to have got off the bus at Linden Place Doveton.
Transit Crime Investigation Unit detectives have released images and CCTV of a man who may be able to assist with their enquiries.
He is described as aged in his early 50s with a medium build, dark skin and greyish facial hair.
He was wearing brown coloured pants, a brown shirt, light-coloured hat and carrying a backpack.
Anyone with information should contact Crime Stoppers.