Police were last night investigating two suspicious fires at a Bedford home and a Fremantle business.
Firefighters were called to the Rosebery Street home in Bedford about 8pm after reports smoke was billowing from the back of the home.
The three bedroom Department of Housing property sustained significant to several back rooms and fire crews were forced to remove roof tiles to gain access to blaze.
It took firefighters 15 minutes to extinguish the fire, which left an estimated damage bill of $300,000.
Neighbours said they frantically tried to check if anyone was in the home at the time but luckily the elderly resident is understood to have been spending the night at a relative's home.
In Fremantle, about 20 firefighters worked to contain a fire at a business in a heritage listed building on Pakenham Street near Short Street about 8.40pm.
Police closed off the street so a combined ladder platform could reach the top of the two storey building.
The blaze caused an estimtged $150,000 damage.
Anyone with information about either fire is asked to call Crime Stoppers on 1800 333 000.