When Natascha Kampusch was last seen on her way to school in a run-down housing estate on the outskirts of Vienna in 1998, she was a four-foot-nine 10-year-old with light brown hair and blue eyes squinting behind blue and yellow glasses.

But now the focus of Austria's most enduring child abduction mystery appears to have emerged as a pale and shaken 18-year-old after years of captivity in the cellar of a house less than 10 miles from where she disappeared.

Local media reports claim she was held captive by a man named as Wolfgang Priklopil, a communications technician who committed suicide last night by throwing himself in front of a train while on the run from the police.

The discovery has stunned the nation, and left Ms Kampusch's father, Ludwig, choking back disbelief. "I really hope this is really true," he said on Austrian television. "I'm betting God this has really happened."

Police said she was in good health despite apparently spending eight years locked in a room described as either a sealed cellar or garage.

"She is white-pale, looking as if she had been out of the light of day for a long time, but she articulated well and could read and write," said a police investigator, according to Austria Presse Agentur.

Police said she had spent the night in a secure location with a female police psychologist and had eaten breakfast this morning.

Ms Kampusch said her captor allowed her occasional walks with him in the neighbourhood and access to radio, television, newspapers and books, and the garage was equipped with a bed and wardrobe, according to police and local media.

She turned up on Wednesday in a garden close to the house where she is thought to have been kept in the town of Strasshof, just outside Vienna. Her home in the postwar Danube estate is less than 10 miles away, on the Austrian capital's eastern fringe.

Austrian television said an 80-year-old man discovered her. She was running, screaming and in a state of panic.

The discovery sparked a major manhunt but Priklopil escaped in a red sports car that was found abandoned in a Vienna car park yesterday.

Officers said the captor was 44 years old and showed a picture of a strong-jawed man with a short brown fringe. They said they were proceeding cautiously in their search of his house due to claims that it may have been booby-trapped with explosives.

Lead investigator Nikolaus Koch told Austrian television that the police had contacted Priklopil about three months after Ms Kampusch disappeared but that he had a "sturdy alibi" at the time. His neighbours had told police that he was unsociable and kept himself to himself.

Forensics experts are still awaiting the results of a DNA test to confirm the abducted woman's identity but said that an operation scar on her arm was identical to one Ms Kampusch had, and that they were "quite sure" it was her.

Her passport had been found in Piklopil's house and her father, mother and half-sister had all identified her, police said. Her sister Sabina Sirny told Austrian television that their mother had broken down when she was told of the discovery on Wednesday. "She always said [Natascha] was still alive," she said.

Despite Austrian media reports that she had been kept as a sex slave a police medical examination showed no signs of injury or sexual abuse. However, police suggested that she may have become resigned to her captivity due to Stockholm syndrome, a condition that sometimes causes kidnapped people to sympathise with their abductors.

Ms Kampusch's abduction at 7am on March 2 1998 dominated local headlines for years, coming amid revelations about the series of rapes and murders carried out by Belgian paedophile Marc Dutroux.

The search for her spread across Austria and neighbouring Hungary and claims from witnesses that Ms Kampusch had been seen getting into a white van led prosecutors to investigate possible links with French mass-murderer Michel Fourniret, who was also reported to have used a white van in some of his attacks.

Most had given her up for dead. In March, an Austrian parliamentarian petitioned public prosecutors to dig up a pond in the town of Gänserndorf, citing claims that Ms Kampusch's body may have been buried there.