Police and emergency services including six CFA vehicles and support from FRV responded to a house fire in Wyndham Vale on 12 November.
Investigators were told a house on Dampier Court became engulfed in flames around 4.15am.
A 34-year-old male who was inside the property at the time is assisting Police with their enquiries.
The exact circumstances and cause of the fire is yet to be determined but is being treated as suspicious at this stage.
An arson chemist and detectives are expected to attend the scene this morning.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online atwww.crimestoppervic.com.au