Ballarat CIU detectives are investigating a fire at an abandoned weatherboard house in Hickman Street, near the White Flat Reserve.
The alarm was raised at 12.20am (Wednesday).
Two fire crews turned up from Ballarat City and Lucas.
The house was fully involved when they arrived.
Anyone with information should call Crimestoppers on 1800 333 000.
The house (above) before the blaze.