Approximately 35 firefighters responded to a fire at an abandoned house in Boronia late on Monday night.
Several callers to Triple Zero (000) reported the fire on Orchid Avenue just before 11:15pm.
FRV and CFA crews arrived on scene in four minutes and wearing breathing apparatus, worked quickly to contain the fire to about a third of the house.
The brought the blaze under control about five minutes after arriving on scene.
Nobody was inside at the time and specialist firefighters determined the cause was suspicious.
Crews remained on scene overnight to ensure the safety of the scene.
Reviewed 23 June 2021