A Balga man threatened firefighters as they fought to save his home early this morning.
Police are examining the Princess Road property today after the alleged discovery of a hydroponic drug setup.
Four fire crews rushed to the property about 4am but were unable to stop the blaze destroying most of the house.
A Department of Fire and Emergency Services spokeswoman said police were called to the scene when the male occupant started threatening firefighters.
She said the fire left a damage bill of about $400,000.
Arson Squad officers are investigating the cause.
Anyone with information is asked to call Crime Stoppers on 1800 333 000.