The Arson Squad is investigating the cause of a house fire in Orelia.
The blaze broke out around midday on Monday at the home on Nathaniel Way.
The fire caused extensive damage to the property leaving a bill of $250,000.
It is understood a family of seven lived at the home, including a woman, her son and daughter, four grandchildren and a foster child.
Detectives are asking any motorists who were driving along Christmas Avenue and Nathaniel Way in Orelia between 12pm and 12.30pm on Monday, who have dash-cam vision to come forward.
Anyone with any information relating to this fire is asked to call Crime Stoppers on 1800 333 000 or report online at www.crimestopperswa.com.au.
Rewards of up to $50,000 are available for information that leads to the apprehension and subsequent conviction of an arsonist.
Locals urged to look out for man who removed electronic monitoring device
Four charged over brutal Warnbro home invasion allegedly linked to illicit tobacco trade
UPDATE: Sadly the whale has died overnight
City of Rockingham records steep increase in animal cruelty complaints related to untreated medical conditions
Accused dirt bike hoons charged by Mandurah Police
Heavy rainfall, thunderstorms to lash Mandurah down to Busselton
Drivers escape serious injury after West Pinjarra, Baldivis crashes
Police investigate stabbing of two men at Warnbro home
Shark sighted in Dawesville Channel