An Austrian judge ruled Friday that a man suspected of keeping his daughter captive in a dungeon for more than two decades should remain in custody, an official said.
The decision extends Josef Fritzl's pretrial detention by a month, St. Poelten provincial court spokesman Franz Cutka said. It was made during a routine, closed-door session required under Austrian law and will be re-evaluated in June.
Fritzl's lawyer could not immediately be reached for reaction.
Fritzl, 73, was formally placed in confinement April 29. He had been detained three days earlier on suspicion of locking up his daughter Elisabeth for 24 years and fathering her seven children.
Authorities say Fritzl has told investigators three of the children were raised in a cellar at his home in Amstetten, three others were brought up above ground, and one died in infancy.
Prosecutors are investigating Fritzl for rape, incest, coercion and the death of the baby, though he has not been charged. Police say he has admitted incarceration and incest.
The head of the police investigation, Franz Polzer, told Reuters on Friday the house above the cellar, in the small town of Amstetten, was being minutely examined.
Fritzl's alleged double life began to fall apart when Elisabeth's oldest child, a 19-year-old woman, was hospitalized with a severe infection.
Unable to find medical records for the woman, doctors appealed for her mother to come forward. Fritzl accompanied Elisabeth to the hospital April 26 and was detained after she divulged what had allegedly happened to her.
'Must have been crazy'
In comments relayed through his lawyer and published in the Austrian magazine News on Thursday, Fritzl was quoted as saying he knew it was wrong to hold his daughter captive and that he "must have been crazy" for doing so. He added that he tried to care for her and their children as best as he could by taking them flowers, toys and books, according to the interview.
Police on Friday said their investigation on the grounds and the cellar was largely complete except for some specialist electrical and electronic examination.
"We have been using sniffer dogs and ground radar in order not to have to dig up the whole area," Polzer said.
Police still believe Fritzl had no other secret hideaways. "This prison was so complex, so extensive that this exhausted Mr. Fritzl's capabilities," Polzer added.