The arson squad is investigating two deliberately lit fires that damaged homes overnight.
Firefighters were called to a unit in Mirrabooka about 8pm after reports of smoke coming from the back door.
Crews were able to get the fire on Australis Avenue out in less than 15 minutes however neighbouring properties were left smoke logged.
It is understood when crews arrived the back door was unlocked and the owner, who was not home when the fire started, later told investigators they did not recall leaving it open.
A vehicle was stolen from the residence, and was later located burnt out.
Firefighters were called to a second house fire in Belmont just before midnight.
The blaze caused about $100,000 damage.
A WA Police spokesman said the Arlunya Avenue residence had been broken into and the fire deliberately lit.
“The occupant of the house was able to escape before the fire caused significant damage,” the spokesman said.
Arson squad detectives remained at the scene of the fire this morning conducting further assessment.
Anyone with information regarding either fire is asked to call Crime Stoppers on 1800 333 000.
Another house fire in Dudley Park caused significant damage overnight.
The fire started just after midnight but is not believed to have been deliberately lit.
Damage is estimated at $350,000.