DNA: Sex captor fathered daughter's children

AMSTETTEN, Austria (CNN) -- DNA testing has confirmed that Josef Fritzl, who police say confessed to holding his daughter hostage in underground rooms for more than two decades, fathered seven children with her, an Austrian law enforcement official said Tuesday.

"It is clear now (that) the six children of Elisabeth Fritzl, that she bore ... that this is the father, who is now 73 years old, something that we, from a criminal point of view, we have never met such a case. Astonishing," said Franz Polzer, director of the Lower Austrian Bureau of Criminal Affairs.

The seventh child died shortly after birth, and Fritzl told police he burned the infant's body in an oven, authorities said. Though its body was not available for DNA testing, police said it was a twin to one of the six tested.

Fritzl's DNA also was found on a letter sent to the Fritzl family that was made to look like it was from his daughter, Elisabeth, Polzer said.

Authorities said Fritzl sent other such letters over the years, leading the family to believe that Elisabeth was a runaway who had abandoned three of her children on the Fritzls' doorstep.

Those three children lived in the home above the cellar prison -- in which the three other children remained -- with Fritzl and his wife, Elisabeth's mother, Rosemarie.

Authorities said it doesn't appear that Rosemarie Fritzl was involved in or knew about her husband's activities. See inside the 'House of horrors' »

She had talked to her friend Gertrude Baumgarten about one of the infants left on her doorstep.

"She said she believed her daughter had had the child with someone from the cult and couldn't take care of it. That's why Elisabeth laid it in front of the door.

"And [Rosemarie] said, 'Well, what can we do? We have to take the child in,' " Baumgarten said.

"She never knew that something was so very wrong there," she said, adding, "I believe it would be fitting to get a rope and hang him. Such a pig!"

Reports have surfaced in The Times of London and Austria's Presse that Fritzl was convicted of sexual assault in the 1960s, but there is nothing in his record to confirm this, District Governor Hans Heinz Lenze said. He added, however, that records are expunged after a certain number of years.

Prosecutors are checking back records to try to find this information, said Gerhard Sedlacek, prosecutor for the state of Poelten.

The Times of London quotes a 50-year-old neighbor who said that when he was 10, he remembered "how we children were afraid to play near Mr. F's house because of the rumors that he had raped a woman and spent some time in jail for it."

Fritzl led police to the cellar, which has about 100 square feet, on Sunday. A day later, he confessed to raping Elisabeth, now 42, and keeping her and their children in captivity in the cellar for years, police said.

Josef Fritzl was able to convince social service workers, friends and family that Elisabeth had run away in 1984, when she was about 18. Police describe him as an authoritarian figure, forbidding anyone in the family from entering the cellar.

In the cellar with Elisabeth were a daughter, Kerstin, 19; and two sons, Stefan, 18; and Felix, 5.

The three children held in the cellar in the town of Amstetten were still in the hospital Tuesday after their horrific ordeal.

The eldest of the children, Kerstin Fritzl, was in an induced coma.

Stefan and Felix are said to be doing "surprisingly well and in good health," considering that they had never been exposed to sunlight, CNN's Phil Black said. The boys are still undergoing medical treatment, he added.

Police said Tuesday that they have searched other properties belonging to Fritzl to make sure there are no other similar situations. Nothing has been found, they said.

Also Tuesday, a judge ordered Fritzl to remain in custody. He appeared calm and showed no emotion in court, according to an Austrian reporter present.

Some neighbors have lived in the area for 30 years and not only knew Josef Fritzl but also knew Elisabeth as a youngster, said Maria Otto Pries, who has lived in the area only three years and did not know the family.

"Many people have shaken his hand and said hello and gone to the same bakery with him and had a coffee with him at the coffee shop," she said. "The scarier fact is that it happened just around the corner." See how Austrians are troubled by the case »

Thomas Birgfellner, a reporter with Austrian broadcaster ORF, said there was a strong belief that, with his expertise as a former electrical engineer, Fritzl -- who installed an electronic security door in the cellar -- must have had help from other people.

"Everyone has said he could not do it alone. He could not install it alone, and now they have to investigate if there were some other people who assisted him," Birgfellner said.

It was Kerstin's serious condition that led to the unraveling of the case over the weekend, forcing Josef Fritzl -- who she thought was her grandfather -- to take her to the hospital in Amstetten, west of Vienna.

Kerstin's mother, Elisabeth, begged Josef Fritzl to take the teen to the hospital.

Josef told his wife that their missing daughter had dropped off ailing Kerstin on the doorstep with a note asking that they get her medical care.

Josef took her to the town's clinic with the note, but doctors needed more information to determine why the young woman was unconscious and having violent convulsions.

So they contacted police, who asked the local media to report on Kerstin's situation in an effort to find the missing mother.

Elisabeth and her two sons saw the reports on the television provided to them in their living quarters, Polzer said, and "they desperately pleaded with their father so they could be taken [to the hospital] ... [and] do something for the 19-year-old."

Josef Fritzl agreed and took all three of the remaining captives out of the basement, explaining to Rosemarie and the rest of the family that Elisabeth had reappeared with her two children after 24 years. Watch a report of how the case unfolded. »

He took them to the hospital, and authorities there realized that something was wrong. Police picked up both Josef and Elisabeth on Saturday near the hospital and brought them into the station for questioning.

Josef would not talk to police, but Elisabeth began to tell her story once she was convinced that she would never have to see her father again and that her children would be safe.

She told police that her father began sexually abusing her at age 11.

On August 8, 1984, weeks before she was reported missing, her father enticed her into the basement, where he drugged her, put her in handcuffs and locked her in a room, she told police. E-mail to a friend

CNN's Phil Black, Nadine Schmidt and Eileen Hsieh contributed to this story.

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