A man who imprisoned his daugher in his cellar for 24 years and fathered seven children by her planned and built her prison when she was just 12 years old, it has emerged.
At a press conference, Austrian authorities revealed that Joseph Fritzl constructed a dungeon below his house in which to keep his daughter, Elisabeth - and added that he must have had help to do it.
He started planning to build the windowless prison, which was separated from the house by eight locked doors, as long ago as 1978, authorities involved in the case said.
He then forced Elisabeth to live in the dungeon, where he repeatedly raped her, while telling his wife she had run away to join a cult.
Three of her children were forced to live in the dungeon, while another three were taken upstairs to live.
The eldest of the imprisoned children is fighting for her life in hospital - the need to get her medical help was what led to their discovery.
Kirsten, 19, is in intensive care and said to be breathing weakly.
All the other members of the family, including Fritzl's wife, are now learning how to live together, and those who lived underground are slowly adjusting to daylight and being around other people.
Austrian prosecutors say they will meet Fritzl for the first time on Wednesday or Thursday.
The 73-year-old suspect has not yet been charged, but his lawyer has said he is preparing an insanity defense.
Earlier, Fritzl's sister-in-law, identified only as Christine R, said she had been scared by Josef Fritzl, 73, when they met at family gatherings.
He instilled a culture of fear in his home, she added.
"When he said it was black, it was black, even when it was 10 times white," she said.
"He tolerated no dissent."

Josef Fritzl
Austrian man who imprisoned his daughter
Copyright © 2008 Yahoo! All rights reserved.