Wyndham Crime Investigation Unit officers are investigating criminal damage to a business in Hoppers Crossing last month.
A witness was inside a business on Graham Court about 5.30am on 5 February when they heard a loud cracking sound outside.
The witness found the upper floor of the building full of smoke then looked out the window and saw a car parked out the front on fire.
He went outside and found the businesses office area was also on fire so used a hose to put it out before calling emergency services.
The witness did not sight anyone, but a large jerry can was located at the scene.
Investigators have released images of a four door Mercedes sedan seen in the area and a man they believe can assist with their enquiries.
Investigators are urging anyone who recognises the vehicle or with information to contact Crime Stoppers on 1800 333 000 or submit an anonymous report online at www.crimestoppersvic.com.au.