AROSN Squad detectives are seeking public assistance after a motor home was destroyed near Dwellingup last week.
Between 4.30pm and 9.30pm on Thursday January 4, the parked 40-foot luxury coach was set on fire on Pinjarra-Williams Road, near Inglehope Road in Inglehope.
The motor home was destroyed by the fire and the damage is estimated to have caused more than $150,000 in damage.
Investigators have requested anyone travelling in the area during the above times who may have dash cam footage to come forward.
They have asked anyone who saw any suspicious activity in the vicinity to call Crime Stoppers on 1800 333 000.
Rewards of up to $50,000 are available for information which leads to the identification and conviction of an arsonist.