Detectives from Banyule-Nillumbik Crime Investigation Unit are investigating a collision in Eltham last month.
It is understood a white 2016 Holden Colorado utility, and a white 2021 Toyota Corolla sedan collided on Bolton Street about 7am on Thursday, 11 December.
Officers have been told both drivers pulled over to the side of the road to exchange details and assess the damage to the vehicles.
The unknown driver of the Toyota provided false details to the driver of the Holden, before gathering some personal items from the vehicle and fleeing on foot south on Bolton Street.
The driver of the Holden, a 59-year-old Epping man, was not injured in the collision.
Police attended the scene and while searching the Toyota, located a firearm inside the passenger seat footwell.
Subsequent checks of the Toyota revealed that it was bearing cloned plates at the time of the collision.
Investigators have released an image and CCTV of a man who may be able to assist with their enquiries.
He is perceived to be Caucasian in appearance, thought to be in his late 20's or early 30's, has short brown hair and was unshaven.
He was seen wearing an orange hi-vis long-sleeved shirt, blue work pants and tan work boots.
Anyone who witnessed the incident, has dashcam/CCTV footage, or information is urged to contact Crime Stoppers on 1800 333 000 or log onto www.crimestoppersvic.com.au
