Dad admits to raping daughter

Tenant: Incest dad's son entered cellar
Story Highlights
NEW: Former tenant says he saw Fritzl's son enter basement
NEW: Noises from basement explained away as a heater in a boiler room
Incest dad spent entire days and nights in cellar, sister-in-law tells newspaper
Josef Fritzl kept daughter imprisoned for 24 years; fathered her seven children
AMSTETTEN, Austria (CNN) -- A man who previously rented an apartment from a now-73-year-old man accused of holding his daughter captive in his cellar for 24 years said Thursday that he saw the man's son enter the off-limits basement.
Alfred Dubanowsky said he rented a ground-floor apartment at Josef Fritzl's home from 1995 through 2007. He said there was a verbal agreement between Fritzl and the house's tenants that they were not to enter the cellar or the garden or photograph the premises, or they would be kicked out.
Police said Monday that Fritzl also made clear to his wife and children that they were not allowed to go into the basement.
Fritzl has confessed to keeping his daughter Elisabeth in the basement for more than two decades, where he repeatedly raped her and fathered seven children with her, six of whom survived, police say.
Dubanowsky said he saw Fritzl's son, also named Josef Fritzl, enter the cellar. He also saw the elder Fritzl enter the basement frequently at night.
Once, when he asked to talk to the younger Fritzl, the older man said his son was working and "not to distract him," Dubanowsky told CNN's Frederik Pleitgen.
It was not clear whether the younger Fritzl went into the secret section of the cellar where police said the woman and children were kept or whether he knew of their captivity.
Dubanowsky said he heard strange noises coming from the cellar sometimes, but Fritzl told him it was coming from the heater in the home's boiler room.
The police investigation will examine whether any accomplices were involved in the case, but police spokesman Franz Polzer said there were "neither technical nor biological traces of any other person in cellar" other than Fritzl.
Meanwhile, Fritzl's sister-in-law said in an interview published Thursday that the man often spent many hours in the cellar and would sometimes stay there all night.
"Every day at 9 in the morning, Josef would go into the cellar," the woman, identified as Christine R., said in the article on the front page of Austria's Oesterreich newspaper.
"He said he was drawing engineering plans that he would sell to companies," said the woman, the sister of Fritzl's wife. "Often, he would stay there all night." She said his wife was not even allowed to bring him coffee.
Fritzl is alleged to have threatened to gas his prisoners if they harmed him or tried to escape, The Associated Press reported.
Austrian authorities said the imprisoned children, who for years had not seen the light of day, were slowly adapting to sunlight. Officials also debunked reports in a few British newspapers that some of the children could not walk or speak in sentences.
The story of the family's imprisonment began to unravel a week ago, when Elisabeth Fritzl's oldest daughter, Kerstin Fritzl, fell seriously ill with convulsions and was hospitalized.
The 19-year-old girl, who was locked in the basement along with her mother and two brothers, remains in an induced coma in an Amstetten clinic. She is suffering from a kidney ailment that worsened because she did not receive medial treatment sooner, authorities said.
"We cannot expect any dramatic changes in her condition in next few days," Dr. Albert Reiter said. "We will make every effort to help as best as we can; perhaps in a few weeks we hope some positive change for the better."
Fritzl had told his wife that Elisabeth, now 42, ran away from home at 18, police say.
The Fritzls adopted three of the children who Josef said were left on his doorstep as infants by his runaway daughter. Fritzl has confessed to incinerating the body of the infant that did not survive, according to police.
Fritzl has yet to be charged, but he can be held by police for 14 days without formal charges while the investigation is under way. That amount of time can be extended by a judge.
A spokesman for the prosecution, Gerhard Sedlacek, said Fritzl had stopped talking to police since making his initial confession. Investigators intend to begin questioning him again next week, Sedlacek said.
Austrian police spokesman Franz Polzer said the investigation would probably last a couple of months. Police plan to interview at least 100 people who lived in the same apartment building as the Fritzls over the past 24 years.
Authorities are looking into reports that Fritzl may have had a rape conviction in the 1960s but have no information because criminal records are expunged after a certain number of years under Austrian law.
However, Polzer denied reports that authorities were looking into Fritzl's ties to the unsolved murder of a young woman more than 20 years ago.
During the time Fritzl owned a hotel and restaurant at a lake in Austria, a woman was found murdered at the other end of that lake, Polzer said.
Police are aware of the media reports and may investigate possible links in the future, but at this time, Polzer said, there is no investigation.
On Sunday, Elisabeth and her two sons, ages 18 and 5, met the three children who were raised by Josef and Rosemarie Fritzl, unaware that their mother and siblings were kept prisoners in the basement.
"It is astonishing how easy it worked, that the children came together, and also it was astonishing how easy it happened that the grandmother and the mother came together," clinic director Berthold Kepplinger said Tuesday.
Authorities are looking into the possibility of giving new identities to the Fritzl family. District Governor Hans Heinz Lenze said Tuesday that the Fritzl name had been "muddied" by the case.
On Wednesday, a German tabloid released video of Fritzl laughing on a Thai beach and receiving a massage, apparently as his daughter and three of their children remained locked up in his basement.
The newspaper Bild posted the video on its Web site and said it was taken and provided to the newspaper by Fritzl's friend, a retiree from Munich.
Copyright 2008 CNN. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed. Associated Press contributed to this report.

This is so digusting, at least he admit to doing this. If you were in his daughters shoes...would you have tried to escape??