Wolfgang Priklopil was a 44-year-old telecoms technician
More details have emerged in Austria suggesting that a woman found near Vienna on Wednesday is a schoolgirl who vanished eight years ago.
The passport of Natascha Kampusch was found at the house where she was allegedly imprisoned and the woman had the same distinctive scar as the girl.
DNA test results are due later on Thursday which Austrian police expect will confirm the woman's identity.
The suspected kidnapper died after throwing himself in front of a train.
The man, named in Austrian media as Wolfgang Priklopil, had been chased by police earlier on Wednesday evening and his red BMW car was later found abandoned.
The schoolgirl's disappearance at the age of 10 had sparked a huge manhunt eight years ago.
The woman says she is Natascha Kampusch and relatives of the missing girl say they are confident she is telling the truth.
The woman - said to be in good health - says she was abducted and held captive in a sealed garage at the house in Strasshof, in the Gaenserndorf area on Vienna's northeastern outskirts.
Police were called when she was found staggering in a garden nearby.
It is not clear what the kidnapper's motives were. Police say he had no connection to the girl's family and there had been no ransom demand.
A police investigator told the BBC's PM programme that "he gave her food, he gave her all the supplies she needed".
"He gave her books, even taught her how to read and how to write, and mathematics and all things like this, according to what she told us."
Police have searched the garage, and say it looked like a dungeon.
Austrian media report that the room had a cavity measuring four by three metres (yards), with an entrance measuring 50cm by 50cm. They believe it was blocked with a sound-proof safe whenever the kidnapper left the scene.
A bed and bookshelf with children's books were reportedly also found there.
"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," the Austria Press Agency quoted a police investigator as saying.
APA also reported that she burst into tears on Wednesday night when she met the man believed to be her father, Ludwig Koch, at the police station.
Ms Kampusch's disappearance in 1998 shocked Austria and triggered a search that extended into Hungary and included the dredging of riverbeds.
The young woman says she was held captive for eight years
According to police, before committing suicide Wolfgang Priklopil had called a friend for help on Wednesday, saying he was being pursued by police for drink-driving.
Psychologists quoted by Austrian media say they believe the woman suffered from "Stockholm Syndrome" - a psychological condition in which captives begin to sympathise with their kidnappers.
Priklopil had been questioned by police in April 1998, as one of more than 1,000 owners of white vans. He was later released. A schoolfriend of Ms Kampusch had told police the girl had been abducted in a white van.
Police are investigating whether the woman had been beaten or sexually abused by the kidnapper.