A pizza delivery man was robbed after an armed man jumped onto the road in front of his scooter in Dianella last night.
Insp David Picton-King said the robbery happened at the intersection of Avocado Drive and Majestic Parade about 9pm.
Insp Picton-King said the delivery driver, who worked for Domino's Pizza in Mirrabooka, was on a job when the man stopped him and threatened him with what appeared to be a small handgun.
The victim handed over cash and the man fled.
Police were last night searching for the man, who is 15 to 16 years old and was wearing a baseball cap and a black hooded jumper.
Anyone with information is asked to contact Crime Stoppers on 1800 333 000.