A cupcake led to the downfall of a couple accused of a 'Bonnie and Clyde' series of robberies across Brisbane's north.

A 25-year-old Beenleigh man and a 23-year-old Alexandra Hills woman are helping police with their enquiries following a dramatic arrest that started with a stolen cupcake and ended with the help of the dog squad and the police helicopter, PolAir 2.

The couple are thought to have forced a 27-year-old woman from her car in Chermside on October 28, later that same day, they are accused of forcing a 70-year-old woman from her vehicle in Toowong. The elderly woman was almost run down by the fleeing couple.

Footage of the couple was distributed, but it wasn't until Saturday afternoon when the couple entered a private event at the Mater Hospital and took a cupcake that police managed to track them down.

They were recognised by an off-duty police officer who called for back up and after a short chase through Salisbury, which was ended with the assistance of the dog squad and PolAir 2, the couple were taken into custody.

The couple was charged late Sunday night, with the female receiving 28 charges and the male to face 28 charges.

They are due to appear in Brisbane Magistrates Court on Monday.