Dungeon dad also raped wife's sister

London, July 31 : Austrian incest fiend Josef Fritzl raped his wife's sister, it has been claimed.

The revelation came to surface after diaries were found in the monster's house, according to police sources.

Fritzl locked his daughter Elisabeth in a secret cellar at his home in Amstetten, Austria, for 24 years ago and subjected her to brutal rapes. She bore him seven children, reports the Mirror.

Elisabeth, now 42, was freed in April after her daughter Kerstin, 19, became dangerously ill and was taken to hospital.

Meanwhile, the devil's wife Rosemarie, 69, said she will divorce him after his trial in the autumn.

She joined Elisabeth and her children in a psychiatric clinic after his arrest but moved out after a rift developed.

ANI