Transit Crime Investigation Unit detectives are investigating after a slingshot was fired at a bus in Coburg on 25 July.
The male offender was seen walking west along Moreland Road, taking shots at several windows and signs.
He then targeted a bus that had stopped to collect passengers on Moreland Road, firing a shot which struck and shattered the window about 1pm.
Luckily the projectile didn't penetrate the glass and the 22-year-old male victim wasn't injured by the broken glass.
Detectives have released CCTV and an image of a man they believe can assist with their enquiries.
He is perceived to be Caucasian in appearance, with a medium build and was wearing a bright blue jacket, light grey track pants, dark-coloured boots and a black bum bag.
Investigators wish to speak to anyone who can identify the man, who witnessed the incident or has CCTV/dashcam footage of the incident.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or visit www.crimestoppersvic.com.au and lodge a report.