The Austrian government has admitted for the first time to lapses in a probe into the disappearance of a woman kept prisoner and raped by her father for 24 years in a windowless dungeon.
The admission came ahead of the first questioning by a regional prosecutor of Josef Fritzl, 73, who has admitted subjecting his daughter Elisabeth to years of sexual abuse in a bunker beneath the family home in eastern Austria.
Elisabeth Fritzl, now 42, bore seven children to her father who had told authorities at the time that she had run away at 19 to join a religious sect.
"I consider that there was a certain credulity (on the part of the authorities), particularly concerning the story of the sect by which the suspect explained the disappearance of his daughter," Justice Minister Maria Berger was quoted as saying in today's edition of the Standard newspaper.
"Today it would certainly be examined more closely," she said - the first time the Austrian authorities had conceded any shortcomings in the grim case that has shocked the nation.
Fritzl had already been convicted of rape in 1967 and spent 18 months in prison.
But authorities did not examine his criminal record when he later adopted three of the children he fathered with Elisabeth, pretending she had left them on the doorstep, according to press reports.
"We wish however that this procedure had been followed even though these were adoptions by family members," Berger said.
Fritzl today faces questioning from the regional prosecutor, Christiane Burkheiser, for the first time.
Experts have said the incest victims will carry the scars of their ordeal for the rest of their lives, although doctors say the family has made progress since their release.
Three of Elisabeth Fritzl's children were held alongside her, living all their life underground, never even seeing natural daylight.
One died soon after birth and the other three were raised by Fritzl and his 69-year-old wife as their "grandchildren" in the house upstairs, unaware of the fate of their siblings underground.
"They remain in a very extreme and difficult situation," said Berthold Kepplinger, doctor at the Amstetten-Mauer psychiatric clinic where Elisabeth Fritzl, her mother and five of her children are recovering.
"The fresh air, the light and the balanced diet are doing them good," he said, adding that the youngest child, a five-year-old boy, "is growing livelier by the day. He's a real charmer, funny and sociable."
The eldest child, Kerstin, 19, is still fighting for her life in intensive care, where she has been placed in an artificially-induced coma and on a life-support machine.
The victims suffered a lack of vitamin D from the absence of natural daylight and possible motor deficiencies resulting from growing up in cramped conditions.
Even the three children who lived upstairs with Fritzl would face problems, said Paulus Hochgatterer, a child psychologist coordinating the team of experts looking after family.
"The man who provided for them, the father figure, has been arrested and is now suddenly the perpetrator," Hochgatterer said.
Fritzl himself is soon due to meet a psychiatrist for the first formal evaluation of his mental state. Adelheid Kastner will meet Fritzl, currently sharing a cell in a regular prison, at an as yet unspecified date.
Meanwhile, Elisabeth's lawyer has said she may sue her father for compensation.
Lawyer Christoph Herbst said he was looking into claiming compensation from Fritzl, who had four or five real estate assets in his name, for those who had been locked in the basement.
"There is the possibility of claiming compensation for imprisonment and the damage that has been incurred by it," Herbst said in an interview.
But Fritzl's assets also have debt attached to them and it is unclear how much money will be left in the end, he said.
"Now it is all about evaluating his financial circumstances. Does he actually have any wealth so that it pays off to start proceedings?"