Vandals are believed to have set fire to an excavator being used to dismantle the Old Mandurah Bridge.
Police and Department of Fire and Emergency Services were called to reports of an excavator on fire at around 1:30am on Wednesday morning.
The excavator is being used in the demolition of the old Mandurah Bridge on Pinjarra Road in Mandurah.
Damage to the excavator is estimated at $100,000.
The fire is being treated as suspicious and investigators would like to speak to anyone who was in the vicinity of the old Mandurah Bridge between 1am and 2am who may have seen any suspicious vehicles or persons in the area.
Rewards of up to $50,000 are available for information that leads to the identification and conviction of an arsonist.
Anyone with any information is asked to call Crime Stoppers on 1800 333 000 or report the information online at www.crimestopperswa.com.au.
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