Williams police are appealing to the public for information, saying two men allegedly broke into the Darkan depot and stole a range of equipment and fuel.
Police say about 9.45pm on September 12, two men travelling in a white Toyota HiLux with a black tray forced entry into the depot on Horwood Street.
Several items are believed to have been stolen during the incident, including a silver fuel tank trailer with WA registration AW5408, Stihl chainsaws, and Milwaukee impact guns.
Police are asking anyone who saw the incident to come forward.
CCTV and dash-cam footage can be directly uploaded online.
Anyone with any information that may help the investigation is asked to contact Crime Stoppers on 1800 333 000.
Reports can be made anonymously.
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