Transit Crime Investigation Unit detectives are hoping to identify a man who performed a lewd act in the presence of a child in Craigieburn earlier this month.
Police have been told the man boarded the 541 bus from a shopping centre on Craigieburn Road about 5.30pm on 7 December.
While on board, he performed a sexual act while a child was nearby.
Police have released an image of a man who they believe can assist with their enquiries.
The man is perceived as Middle Eastern or Southern European in appearance and about 65 years old with a thin build and white hair.
He was wearing gold-rimmed sunglasses, faded blue jeans, black sneakers and a taupe-coloured jacket.
It is believed the man has been seen in the Craigieburn and Broadmeadows areas.
Anyone who recognises him or has information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au
