The girl has been held in isolation since the age of seven and following an investigation it has been shown that the now 18-year-old girl has no disability, the City Malmö newspaper reported.
The girl has spent the last eleven years in the care of her father, without going to school and has been considered to be infantile, unable to express herself in any other way than sounds and body language.
To care for her, her father received welfare totalling 25,000 kronor a week.
The revelations which emerged from the recent medical assessment of the girl are expected to lead prosecutors to soon file charges against the father at Malmö District Court on counts of aggravated fraud and benefits crimes.
Everything came to light when the girl ran away from her parents and reported her father for unlawful threats.
She was taken into care and placed in a youth home, where the social services carried out an investigation into how she, contrary to all previous diagnoses, has a high level of functionality.
The father, who was arrested last summer, is now suspected of having instructed her how to behave in contact with social services, doctors and psychiatrists with the result that she was granted personal assistance 98 hours a week, the newspaper said.
After the revelations the father has been prohibited from having contact with his daughter.
Deputy chief prosecutor Bo Birgerson, who is leading the preliminary investigation has confirmed to the newspaper that the scam runs into several million kronor.