London, May 5 : Policemen probing into Joseph Fritzl's shocking incestuous assault on his own daughter Elisabeth Fritzl say that her first two children should have witnessed her being raped repeatedly by her father, from the day they were born until they were toddlers.
The police say Elisabeth was held in only one room in the bunker for the first nine years after Joseph dragged her into his cellar, and that it was in 1993 that the room was connected with other underground chambers in the complex.
Fritzl and Elisabeth's first child Kerstin was born in 1989, and second child Stefan in 1990.
Since the two children spent their whole lives inside the cellar, say the police, they would have had no choice but to witness their mother being repeatedly abused.
The police have also revealed that Fritzl adopted Elisabeth's third child Lisa, born in 1992, because there was insufficient room in the cellar.
According to them, Fritzl allowed the girl to live with his "normal" family in his house upstairs.
The dungeon father later extended his underground bunker complex to provide a separate room for his prisoner children, add the police.
Meanwhile, Fritzl's lawyer Rudolf Mayer, who claims to have received several death threats for agreeing to defend his client, has said he would fight to keep Fritzl out of jail.
"In my opinion Josef Fritzl is psychologically disturbed. He does not belong in prison but in a closed psychiatric unit," the Independent quoted him as saying.