Two boys are among four people arrested after a spate of alleged petrol station robberies in Adelaide's northern suburbs within an hour of each other on Wednesday night.
Police will allege two males entered a service station on John Rice Avenue, Elizabeth South, with a knife at 9:45pm and threatened a staff member.
However, they left the store empty-handed.
About half an hour later, another service station on Port Wakefield Road, Cavan, was allegedly robbed in a similar manner, with the console operator handing over cash and cigarettes.
Another 15 minutes later, two males armed with a knife allegedly threatened staff at a service station on Bridge Road, Pooraka, and stole cash from the store.
Soon after, they also allegedly robbed a service station on North East Road, Modbury.
Afterwards, police stopped a white ute nearby and arrested two suspects immediately and then another two who were allegedly found near a creek and in a back street.
A 24-year-old Andrews Farm woman, a 22-year-old Modbury man, a 17-year-old Craigmore boy and a 14-year-old Northfield boy have been charged with aggravated robbery and theft.
They will face court later on Thursday.
Police said no-one was physically injured during the alleged robberies.
All of the service stations robbed were part of the OTR chain, the largest in South Australia.