By Sylvia Westall
VIENNA (Reuters) - Austrian police have arrested a man they believe imprisoned his daughter in a windowless basement for 24 years, abused her and fathered seven children with her.
Police said the woman, identified as 42-year-old Elisabeth F, told them her father Josef had lured her into the basement of the block where they lived in the town of Amstetten in 1984, and drugged and handcuffed her before imprisoning her.
Three of her children were locked up since birth in the basement of the drab, grey building along with their mother and had never seen sunlight or received any education, police said.
Authorities in Amstetten, 130 km (80 miles) west of Vienna, were still piecing together details of the case, reminiscent of that of Austrian Natascha Kampusch who spent eight years locked up in a windowless cell before escaping in August 2006.
"We are faced with a crime that is incomprehensible," Interior Minister Guenther Platter said on Austrian television. "Everything that has happened here goes beyond one's imagination".
Josef, a 73-year-old electrical engineering technician by training, told investigators how to enter the basement prison through a hidden door operated by secret code, police said.
"There was a shelf with plenty of cans and containers, and behind the shelf was a door made of reinforced concrete, secured electronically and running on steel rails, and only the suspect knew the code," said local official Heinz Lenze.
The hideout itself was a sophisticated network of chambers with facilities for sleeping, cooking and washing, Franz Polzer, head of the criminal investigations unit in the province of Lower Austria, told broadcaster ORF. Continued...
Police in the Lower Austrian town of Amstetten have arrested a 73 year old man who is alleged to have kept his daughter, now aged 42, locked in the cellar of his house in Amstetten since 29th August 1984. 

The man, identified by police as Josef Fritzl, is alleged to have started sexually abusing his daughter, named as Elisabeth Fritzl, when she was eleven years old, and to have subsequently fathered seven children by her. One of the children, one of a set of twins born in 1996, died of neglect shortly after birth and the body was burned by the father. The surviving six children, three boys and three girls, are currently aged between 5 and 20 years old. Three of the children were left on Josef F.'s doorstep and subsequently raised as the adoptive children of Josef F. and his wife, Rosemarie, while the other three children were left with their mother and never saw daylight until she was discovered. Rosemarie F. is said to have been unaware of her husbands' activities.

Police became suspicious when a 19-year-old daughter, Kerstin, was taken to hospital with a mysterious life-threatening illness, and the family's medical records were checked. Police say that Elisabeth F. appeared to be "greatly disturbed" psychologically, and only agreed to talk after the authorities assured her that she would not have to have contact with her father, and that her children would be cared for.

The news has shocked Austria, recalling the case of Natascha Kampusch who was kidnapped aged 10, and escaped after being held in a "dungeon" for eight years in 2006.

DNA tests are to be undertaken to confirm the paternity of the children.