Police were investigating a fatal crash in Forrestdale that occurred on April 11.
About 6.15am two cars and a truck collided on Tonkin Highway near the intersection of Forrest Road.
The 18-year-old male driver of a Toyota sedan died at the scene.
A 40-year-old man driving a Toyota ute was taken by ambulance with serious injuries but not believed to be life threatening.
The 24-year-old male driver of the Isuzu truck was left uninjured.
Anyone with information about the crash was asked to call Crime Stoppers on 1800 333 000 or make a report online at crimesetopperswa.com.au.