UPDATE: Police have arrested a woman believed to be responsible for a string of armed robberies across Perth today.
The 31-year-old woman was arrested at a Koondoola IGA store about 3:30pm after allegedly beginning a crime spree at the BP service station in Padbury this morning.
She is being questioned by police.
The woman allegedly threatened a man with a knife and stole his wallet while he was filling his car up at the Warburton Avenue business about 7am, before fleeing the scene in a white ute.
Police believe she was involved in a crash on Marmion Avenue in Merriwa a short time later, after which she abandoned the ute.
She then allegedly stole a silver Mazda 3 sedan in Warwick and drove the car to Dianella where police say she robbed the Westpac Bank on Grand Promenade.
After threatening staff, she made off with an undisclosed amount of cash and drove the Mazda to Booragoon, where it is believed she committed another robbery.
Police say she then took a taxi from Booragoon to Koondoola IGA before the driver was able to phone police. The driver restrained her until police arrived.