Two boats were destroyed in a suspected arson attack near Mandurah overnight.
The fire, which started in a boat yard on Quarry Way in Greenfields, was reported about 12:30am.
There were signs of a break-in at the site, Department of Fire and Emergency Services communication supervisor Nigel Elliott said.
The matter has been referred to local police, and forensic officers will investigate.
It appears the blaze was deliberately lit, Mr Elliott said.