Police are hunting a motorcyclist who robbed a pharmacy in Eric Street in Cottesloe last night.
The offender entered the pharmacy about 8pm and threatened a 44-year-old pharmacist with a silver bladed knife and forcing him to open a safe.
He left with a small amount of cash and some prescription medication.
The offender was wearing a motorcycle helmet, black-lens sunglasses, a dark long-sleeved jacket and dark pants.
He is thought to be late 20s to early 30s with a raspy Australian accent, 190cms tall, slightly tanned skin and with black hair.
A witness saw the offender leave on a motorcycle that was parked at the corner of Chamberlain and Florence streets.