Austrian police are investigating a possible link between the man who held his daughter captive in a cellar for 24 years and the unsolved murder of a teenager in 1986.
Regional police chief Alois Lissl said investigators were re-examining at the unsolved murder of a 17-year-old woman near the Mondsee lake near Salzburg, in Upper Austria, in 1986.
Josef Fritzl, 73, and his family were living in a guesthouse they owned in the area at the time of the murder, Mr Lissl said.
The woman disappeared after being seen climbing into a car at a bus stop.
Austrian authorities are to give new identities to the woman held prisoner by her father for 24 years and the children she bore in a cramped cellar.
Police are still questioning Josef Fritzl, 73, who has admitted he fathered seven children by his daughter in a windowless bunker under the family home, while the victims remained carefully shielded in a secret location.
Psychiatrists and doctors are counselling the mother and children on how to come to terms with their ordeal. Experts said they were likely to need years of therapy.
'It could take between five and eight years,' said Max Friedrich, the psychiatrist who looked after another sequestration victim, Natascha Kampusch, in an Austrian press interview.
The head of the local social services, Hans-Heinz Lenze, said a name change had been suggested not just for the immediate victims, but Mr Fritzl's other family as well, in order to give them a new start in life.
'At the moment, all possibilities are being sounded out in closest consultation with the family. But a decision will only be reached in the coming weeks,' Mr Lenze said.
Mr Fritzl has seven children with his 69-year-old wife Rosemarie. His daughter Elisabeth bore him seven more during the 24 years she was incarcerated in a purpose-built 60sqm dungeon where he regularly sexually abused her, according to police.
One of the children died shortly after birth, three remained with their mother, never seeing natural daylight or the outside world, the other three were adopted by Mr Fritzl and lived as his 'grandchildren' upstairs in the family home.
Investigators said DNA tests had shown the retired electrical engineer was the father of the six surviving children.
He has told investigators that he disposed of the body of the dead baby in an incinerator in his building.
Officials revealed that the wood-fired boiler, situated in a heating room just metres away from the cellar where the woman and children were held, underwent a routine inspection by local fire authorities in 1999 without their presence being discovered.
The door leading from the heating room via two more ante-chambers to the dungeon entrance itself was concealed by shelving, said Hermann Gruber, spokesman for Amstetten's mayor Herbert Katzengruber.
'There was no way they (the fire inspectors) could have seen it,' Mr Gruber insisted.
Mr Fritzl's admission that he burned the body could prove pivotal at a trial. A prosecutor said he would face a life sentence if found guilty of manslaughter, as opposed to shorter prison terms for rape or incarceration.
Chief investigator Franz Polzer told Austrian television that police might need half a year to complete their investigations.
With it coming just two years after another case of kidnapping and sequestration, that of Natascha Kampusch, hit the headlines, Austrian Chancellor Alfred Gusenbauer expressed concern over damage to his country's image.
Austrian image marred
One leading marketing professional said Austria was now being called 'the Land of Dungeons'.
In a statement released after a cabinet meeting this morning, Mr Gusenbauer said an international campaign of slander was under way.
'We cannot accept that. There is no 'Amstetten case', there is no 'Austrian case'. There is only an isolated case,' the chancellor said.
Mr Gusenbauer said the 'unimaginable and horrific events' and the 'gravity and abominable nature' of the crime had left many people speechless.
'The government will react with all the means at its disposal' to help the victims, he pledged.
Ministers had been instructed to review all administrative structures that played a role. The federal government would also work with authorities in Lower Austria, where Amstetten is located.
President Heinz Fischer meanwhile also defended his country, saying: 'There is definitely nothing fundamentally Austrian in this case.'
'Monstrosities, that human beings are capable of, manifest themselves everywhere,' he told the daily Kleine Zeitung.
