A photo released by Austrian police shows Josef Fritzl at an unspecified location. (Police Niederoesterreich/Associated Press)

An Austrian man who confessed to locking his daughter in a basement cell for 24 years and fathering her seven children was ordered held in police detention Tuesday as details surfaced of the reunion between the now 42-year-old woman and her mother.

Josef Fritzl appeared before a district magistrate Monday evening and was referred to a higher court in St. Poelten, the capital of the province of Lower Austria.

Prosecutor Gerhard Sedlacek said Fritzl was "completely calm, completely without emotion" when he was placed in pretrial detention Tuesday. He is in a cell where he can be monitored in case he tries to commit suicide, said officials.

He faces up to 15 years in prison if convicted on rape charges, but prosecutors said Tuesday they were examining the possibility of charging Fritzl with "murder through failure to act" in connection with the death of one of the children, which carries a maximum term of 20 years.

Elisabeth Fritzl, 42, said her father first lured her into the windowless cellar that became her prison cell in the town of Amstetten, west of Vienna, in 1984. She endured repeated sexual assaults and gave birth to seven children in the tiny, cramped basement rooms. One of the infants died shortly after it was born, and Josef Fritzl has admitted he burned the body.

Three of the children born in the basement were raised by Fritzl and his wife, Rosemarie, who remained unaware of the horrors taking place in her home, police said.

Fritzl had told his wife that Elisabeth had run away from home at age 18 to join a religious cult and had sent three of her children to be raised by her parents.

DNA test results released Tuesday confirmed that Fritzl is the biological father of the children born while his daughter was in captivity.

Wife and daughter reunite

Also Tuesday, it was revealed that Rosemarie Fritzl and her daughter had an emotional reunion and Elisabeth also met the three children who had been raised upstairs by her parents, freelance journalist David Hill told CBC News from Amstetten.

Hill said psychologists observed the reunions on Sunday and determined that Rosemarie had indeed been unaware of her daughter's presence in the house, and her ordeal.

"It was astonishing how easily it happened — how the mother and grandmother came together," clinic director Berthold Kepplinger told reporters Tuesday.

Elisabeth's other three surviving children, now aged 19, 18 and 5, were confined in the basement with their mother. None of the three had ever been outside of the tiny cramped cellar where they were born. Hill told CBC News that one of the boys had seen the moon for the first time when he was taken from his home by police.

Hospital officials said two of the three children who had grown up in the basement cell met their siblings, who were raised by their grandparents, on Sunday. The other child raised in captivity has been hospitalized due to an illness.

"The children just kind of had this connection, they just got on straight away," Hill said. "Quite emotional scenes."

Officials said Elisabeth and her children are receiving psychiatric treatment in an undisclosed location.

She is "greatly disturbed," officials said, and only agreed to tell police about her father's crimes when she was promised that he would have no further contact with her, or the children.

Investigators search other properties

Also Tuesday, Austrian police inspected other properties owned by Fritzl to ensure he didn't have other underground cells for holding captives.

Franz Polzer, head of the Lower Austrian Bureau of Criminal Affairs, told the Associated Press that investigators believe it is "more than unlikely" that there were other captives.

"We believe he was so busy with his crime that he wouldn't have time for anything else," Polzer said. However, police decided to check his other properties as a precaution.

They didn't find evidence of any other captives.

Officers also continued to search the cell, toting away boxes for further investigation.

Austrians ask: How could it happen?

Hundreds of journalists and television news crews have descended on the usually idyllic area near the Austrian Alps to report on one of the most horrific stories of abuse to emerge in recent years. Austrian commentators and political leaders are demanding a thorough investigation of the case, particularly the fact that no one knew about Elisabeth Fritzl until she told police and medical personnel of the abuse last week.

Her eldest child had fallen gravely ill and was taken to hospital by Josef Fritzl. Medical personnel put out a television appeal for the girl's mother to give them more information, and Elisabeth persuaded her father to let her meet doctors in her first trip outside her basement prison in 24 years.

About 200 residents of Amstetten held a candlelight vigil Tuesday. In steady rain, they sang hymns and prayed for the victims.

In a column in the country's main newspaper, Der Standard, commentator Petra Stuiber said what she termed a "rich, self-satisfied society" needed to ask itself how something so horrible could happen.

"How is it possible that nobody heard or saw anything?" Stuiber wrote. "How can it be that nobody asked questions?"

The commentary was echoed in the Austrian daily newspaper Österreich, which wrote: "The whole of Amstetten should drown in shame."

With files from the Associated Press