Suspected arsonists have inflicted $1 million damage at a Dandenong South car yard in recent months, according to police.
Trucks have been set on fire twice at the business on Kirkham Road in the early hours of February and March.
On 17 February about 1.30am, intruders drove a black Audi to the entrance, forced the gate open and entered on foot.
They are believed to have ignited a fire in a cabin of a semi-trailer which spread to two nearby trucks, police say. One truck was destroyed.
On 3 March about 1.20am, intruders parked a black Ford sedan, cut the gate’s lock and used an accelerant to ignite a Scania prime mover.
Two other trucks also caught alight.
CIU detectives have released CCTV footage in the hope of public assistance.
Any information to Crime Stoppers on 1800 333 000 or crimestoppersvic.com.au
