Josef Fritzl 'kept granddaughter as sex slave'

Josef Fritzl, the Austrian who kept a secret family in his cellar, may have raped one of his own grandchildren, police fear.

They believe Fritzl, 73, may have kept his granddaughter Kerstin, 19, as a sex slave in the windowless dungeon he constructed under his house in the town of Amstetten, west of Vienna.

Medics and detectives have been unable to speak to Kerstin who is in a coma and has suffered multiple organ failure after spending her whole life underground.

Albert Reiter, the doctor treating her, said: "She is in a grave condition and it's impossible to interview her because she is unconscious. We have to wait for a later time to make such investigations."