UPDATED: A 35-year-old woman has been charged with arson after a fire lit in a brush fence at Fullarton after midnight spread to a unit and forced a couple in their 70s to be rescued.
Emergency services were called to units at the corner of Fullarton Rd and White Avenue at 1.30am after reports that a brush fence was on fire.
The blaze then set a unit on fire, with police and MFS officers evacuating the residents, a man and woman in their 70s.
They were not injured but the unit was extensively damaged and the fire took 30 minutes to bring under control.
Two cars were also destroyed.
Police on Thursday afternoon said that detectives went to a Seacliff property and arrested a woman. They said it was not believed to be a random attack.