Major crash investigators are at the scene of a hit-and-run in Armadale.
A police spokesman said the incident happened about 9.30pm yesterday on Lowanna Way, near the Rupert Street intersection.
Two men, aged 20 and 18 years were walking on Lowanna Way when they hit by a car as they crossed the road.
The teenager remains in a critical condition in Royal Perth Hospital this morning. The 20-year-old is in a stable condition with a severed ear and other minor injuries.
A silver vehicle was seen leaving the immediate area at the time.
Police say the car may have damage to one of its side mirrors.
Anyone with information is asked to call Crime Stoppers on 1800 333 000.