Police arrested Josef Fritzl, believed to have fathered seven children with his 42-year-old daughter Elisabeth, who told police that he had abused her from the age of 11.
Fritzl originally lured her into a basement in Amstetten, 130 km (80 miles) west of Vienna, in August 1984, where she was drugged and handcuffed.
The story finally came to light after Elisabeth's 19-year-old daughter, Kerstin, was hospitalized with a serious illness together with a note from Elisabeth on April 19. Following an appeal, the elderly father released his captives, telling his wife that Elisabeth and the children had decided to return home.
When police questioned Elisabeth, however, the full extent of her ordeal started to unfold.
Kersten and two other of Elisabeth's children, aged five and 18, lived in the basement with their mother, while the other three were raised by the father and his wife, and another child died shortly after being born.
Soon after Elisabeth's disappearance her parents received a letter asking them not to search for her. In 1993 a baby was left on the parents' doorstep with a note from Elisabeth followed by two more children, who were all raised by the family, living in the same building as the prison but reportedly unaware of it.
All the children have been taken into care and the mother, who is described as "greatly disturbed" is undergoing medical and psychiatric treatment.
The shocking events echo the notorious case of another Austrian girl, Natashcha Kampusch, who was abducted in 1998 at the age of 10 and held captive by a 44-year-old man for eight years.