A 49-year-old woman was walking along the Glengarriff Crescent in Montmorency on Monday, October 4 at 6pm when she noticed the man behind her.
He reportedly followed her while performing an explicit sexual act.
According to police, she ran to find help from a nearby woman.
The two women then walked together along Wattle Avenue as the man followed them while still performing the sexual act.
He then left the stage was last seen on Baldwin Avenue.
Police have released photos of “a man they believe may be able to help with their investigations”.
“The man is perceived as Caucasian in appearance, aged 25-30 years, with a slender build and blonde hair,” Victoria Police said in a statement.
“He was wearing a gray t-shirt, blue shorts and black shoes. He has a tattoo on his right forearm that shows three stripes.”