Mandurah vehicle theft has declined following a recent police operation targeting fraudulent claims and organised theft.
Mandurah Detectives launched Operation Airplane after more than 500 vehicles were stolen across the district in 2018, from January to October, and 218 remained unrecovered.
A further 241 bikes were stolen between October 1, 2018 and December 31, 2018.
The majority of these were unregistered.
Read More: Stolen motorbike rates prompt crackdown
Mandurah Detective Senior Sergeant Trevor Troy said police introduced a "strict" questionnaire for motorbike owners reporting theft.
Police asked for more information when a motorbike or vehicle was reported stolen, including timeframes, CCTV footage, engine and chaci numbers.
We wanted to ensure people in possession of motorbikes have them lawfully and bring the perpetrators to justice.Mandurah Detective Senior Sergeant Trevor Troy
"My concern was fraudulent claims were at work, along with organised theft by backyard choppers who were on-selling parts on Gumtree and Facebook," Detective Senior Sergeant Troy said.
"We wanted to ensure people in possession of motorbikes have them lawfully and bring the perpetrators to justice.
"Theft of vehicles is down, but we still have a lot more work to do."
Detective Senior Sergeant Troy asked the public to report offenders suspected to be involved in the organised theft of vehicles.
"As well as suspect insurance scams and the like," he said.
Detective Senior Sergeant Troy asked vehicle owners to "ramp up" security practices.
"People need to be securing their keys better at home," he said.