PINJARRA police seized a significant amount of stolen property from a house in Eliza Way, Bertram.
Some items have been confirmed as being stolen and other items are believed to be stolen.
The haul included two quad bikes, a motorcycle, several firearms, ammunition and more than 100 power tools.
A 27-year-old man is currently in custody, assisting with the investigation into items located at the Bertram address.
The police investigation was related to a search warrant at a Greenfields house on Wednesday, October 26, in which about 3000 rounds of ammunition was located, along with other items of interest.
Inquiries are continuing.