Fiery crash ends teen's Queensland crime spree

A 15-year-old boy allegedly tried to rob three businesses in the space of an hour before rolling his getaway car in fiery, high-speed crash in Brisbane.

The crime spree began at Sunnybank Hills, where police said the boy used a knife to threaten a supermarket worker about 10am on Thursday.

He fled without any cash after the worker was unable to open the till and he allegedly then used a knife to demand money from a post office worker at Algester.

The woman fled to the back of the shop and the boy again fled empty-handed before holding up a second supermarket next door.

He grabbed cash and cigarettes before leaving in a stolen Jeep but crashed it, at high speed, into another vehicle shortly afterwards.

The car rolled and caught fire but the boy escaped the wreckage and fled. He was arrested at Kingston late on Thursday night.