A bushfire that threatened lives and homes in parts of the City of Kwinana has been deemed suspicious.
The fire started near Thomas Road in Casuarina just before 4pm on Thursday.
An emergency warning was soon issued for nearby residents, urging them to evacuate their properties.
It took hours for firefighters to extinguish the blaze, with crews spending the night patrolling the area and mopping up.
Thomas Road has now reopened.
Anyone who saw any suspicious activity at the time of the fire is urged to contact Crime Stoppers on 1800 333 000.
The Arson Squad are investigating.