Police begin to piece together tortured life of Elisabeth Fritzl

A shocking image of Elisabeth Fritzl – the 42-year-old victim of Austria's worst recorded case of multiple rape and incest – was published yesterday. It shows an elderly looking woman with crudely cut hair that has turned completely grey. She has a deeply-lined face and tight lips which, doctors say, conceal a mouth full of badly decaying teeth. The drawing, published by the Austrian media, is said to be an "accurate artist's impression" of Elisabeth, based on interviews with doctors and police who have been caring for her since she escaped from the underground cell in which she was held captive for 24 years.

Elisabeth has not been seen in public since she was imprisoned in a windowless bunker beneath her father Josef's garden in 1984 and forced to become his sex slave. Fritzl, 73, who was arrested after apparently confessing to his crimes at the weekend, is in custody pending his trial.

Alois Lissl, the police chief of Upper Austria province, revealed that officers were investigating a possible link to the murder of Martina Posch, who was found on a shore of Lake Mondsee on 12 November 1986, because Frtizl could have been in the area at the "time and place" of the killing.

The artist's drawing of Elisabeth bears little similarity to the only photographs of her published to date – a black-and-white snap of a smiling teenager and a colour picture of her as a 14 year-old secondary school pupil. Observers say she now looks more like the sister of her mother, Rosemarie, who is 69.

Elisabeth spent yesterday with her mother, her children Stefan, 18, and Felix, five – who were held captive underground – along with two of her other daughters, now 15 and 14, and a son, 12, who were allowed to live "normal" lives in the house above the cellar.

The family are being cared for by psychiatrists and social workers in their home town of Amstetten, Lower Austria. She and her family are so traumatised and unused to open spaces or daylight that doctors have placed a cargo container outside their accommodation to allow them to withdraw into a confined space if they need to.

Elisabeth's 19-year-old daughter, Kersten, remains in a serious condition in hospital.

Leopold Etz, one of the police officers who freed Stefan and Felix from the bunker, said he was "staggered" to see the reactions of the children as they tried to adapt to their new surroundings, which they had previously only seen on television.

He added that the boys thought they were in heaven when they emerged, having been told by their mother that "heaven is up there".

Felix has been described as the livelier of the boys, but is also reluctant to leave his mother's side. He was said to have clapped his hands with joy when he saw a cow in a field and is fascinated by the sun and the moon.

Mr Etz said: "When the sunbeams struck his face, he squealed loudly." Yesterday, staff at the hospital caring for the children held an impromptu birthday party with a cake for the second-youngest child, 12-year-old Alexander.

Mr Etz also said that Stefan and Felix used animal-like language to communicate. "They speak with growls and coos. We cannot understand everything they say," he added.

Berthold Kepplinger, the director of the clinic where most of the victims are recovering from their ordeal, said the family members were "talking a lot" with each other. "The family is doing well under the circumstances," he said, considering they had to get accustomed to everyday conditions for others, such as daylight.

Further details of Elisabeth's ordeal, based on a lengthy interview she gave police, emerged yesterday. She had learnt to fear her domineering father from an early age and offered him what appeared to be total obedience. "I don't know why it was so, but my father simply chose me for himself," she told officers. She revealed that Fritzl began sexually abusing her from the age of 11 – in the cellar, in his car and on walks through the forest. Deeply ashamed and frightened of being found out, she did everything possible to hide the truth from her friends and classmates. A former pupil at her school recalled that Elisabeth was "terrified of not being home on time", adding: "When we went to her home, we had to leave as soon as her father appeared."

On two occasions, Elisabeth ran away from home but was picked up by police and sent back each time. In 1984, when she was 18, her father drugged her with ether and dragged her into the cellar, handcuffing her to a metal pole. He kept her in the dark for the first few weeks and visited her only to rape her or give her food. Elisabeth said she faced the choice of being left to starve or being raped.

As Elisabeth began to bear her father's children, Fritzl started improving the bunker and easing her regime. By the early 1990s, he apparently felt relaxed enough to go abroad. A private videotape, shot by one of his friends and released for the first time yesterday, showed Fritzl on a three-week holiday to Thailand in 1994, while his daughter and children were locked up below ground at home.

Questions were being raised over whether Fritzl used an accomplice to provide food for his prisoners during his three-week holidays. The door to the dungeon also weighed 300kg, indicating that hinging the door into place would have required the assistance of a third party.

Fritzl had told his wife that their daughter had run away to join a sect where there was "no room for children". Officers are convinced that Mrs Fritzl believed him.