Bradley Robert Edwards has been found guilty beyond reasonable doubt of the wilful murder of Jane Rimmer and Ciara Glennon.
He was found not guilty of the murder of Sarah Spiers - the first woman who went missing in 1996.
Her body has never been found.
Edwards will be remanded in custody until December 23, when he will receive his sentencing.
Baldivis Police on the lookout for reckless dirt bike riders
Baldivis Police are on the lookout for reckless dirt bike riders.
WATCH: Youths captured on CCTV stealing car in Golden Bay
A group of youths have been captured on CCTV stealing a car in Golden Bay.
Fire crews battle early morning blaze in Warnbro
Firefighters have extinguished a bushfire in Warnbro.
Driver charged over alleged hit-and-run on Mandurah Terrace
A 20-year-old man has been charged over an alleged hit-and-run in Mandurah.
More paramedics, ambulances to be stationed in Dawesville, Australind
More paramedics and ambulances will be stationed in Dawesville and Australind.
Strict demersal fishing bans to come into force off WA coast to save species from extinction
Commercial fishing for demersal fish will be permanently banned off a section of WA's coast along with a raft of other changes to save the under-threat species.
Police call for witnesses to fatal Waroona crash
Police are calling for witnesses to a crash in Waroona that claimed the life of a 55-year-old woman.
WATCH: Confronting footage shows moment car ploughs into teen on Mandurah Terrace
WARNING: This story contains confronting footage.
Teen injured in suspected hit-and-run in Mandurah
An 18-year-old man has suffered a head injury after being hit by a car in Mandurah.