AMSTETTEN, Austria — A man has confessed to imprisoning his daughter for 24 years in a windowless cell with a soundproofed door and fathering seven children with her including three who "never saw sunlight," police said Monday.

Josef Fritzl, now 73, also told investigators that he tossed the body of one of the children in an incinerator when the infant died shortly after birth, said Franz Polzer, head of the Lower Austrian Bureau of Criminal Affairs.

"We are being confronted with an unfathomable crime," Interior Minister Guenther Platter said.

The daughter, who is now 42, had been missing since 1984 and was found by police in the town of Amstetten on Saturday evening after police received a tip. She and the children have been placed under psychiatric care in an undisclosed location.

Authorities on Monday released several photos showing parts of the cramped basement cell, with a small bathroom and a narrow passageway leading to a tiny bedroom. Investigators said an electronic keyless-entry system apparently kept the daughter from escaping from the cell, which was made of solid reinforced concrete.

After initially withholding Friztl's full name, police released it along with a photograph at a news conference Monday. Fritzl's identity was widely reported by media in Austria and elsewhere in Europe. He briefly appeared in court Monday in the city of St. Poelten, where he was to be held in pre-trial detention.

"He admitted that he locked his daughter, who was 18 at the time, in the cellar, that he repeatedly had sex with her, and that he is the father of her seven children," Polzer told The Associated Press.

Three of the surviving children lived with the grandparents and were registered with authorities. The other three — aged 19, 18 and 5 — were confined during their entire lives to the darkness of their cell, Polzer said.

Hans-Heinz Lenze, a senior local official, said the suspect's wife apparently had "no idea" of what went on and was devastated.

"You have to imagine that this woman's world fell apart," he said.

Austrians — still scandalized by a 2006 case involving a young woman who was kidnapped and imprisoned in a basement cell outside Vienna for more than eight years — expressed disbelief at the latest case.

"The entire nation must ask itself just what is fundamentally going wrong," the newspaper Der Standard said Monday in a commentary.

Guenter Pramreiter, who owns a bakery just down the street, told The Associated Press that the suspect and his wife would regularly buy bread and rolls, though never in large quantities.

"They appeared normal, just like any other family," Pramreiter said. "I'm totally shocked, this was next door. It's terrible."

The case unfolded after a gravely ill teenager was found unconscious on April 19 in the building where her grandparents live, and taken to a hospital in the town of Amstetten, about 75 miles west of Vienna. Authorities publicly appealed for the child's mother to come forward to help diagnose the young woman's condition.

After receiving a tip, police picked up the 42-year-old woman — whom authorities identified as Elisabeth F. — and her father on Saturday close to the hospital.

Police said she appeared "greatly disturbed" during questioning. She agreed to talk only after authorities assured her she would no longer have to have contact with her father and that her children would be cared for.

On Sunday evening, police said investigators had found the area where Elisabeth and three of the children were held captive. Investigators said the rooms were at most 5 feet 6 inches feet high. The area had a TV and small hot plates for cooking.

In a chronology of events outlined in a police statement, authorities said Elisabeth told them her father began sexually abusing her when she was 11. She told police that some years later in 1984, he sedated her, handcuffed her and locked her in the cellar.

Police said a letter written by Elisabeth had apparently surfaced a month after her disappearance, asking her parents not to search for her.

The Austria Press Agency reported that the surviving children are three boys and three girls. DNA tests were expected to determine whether Fritzl is the father.

Sunday's developments recalled another case that shocked Austrians in the summer of 2006, when a young woman escaped after being largely confined to a tiny underground dungeon in a quiet Vienna suburb for more than eight years.

Natascha Kampusch was 10 years old when she was kidnapped in Vienna on her way to school in March 1998. Her abductor, Wolfgang Priklopil, threw himself in front of a train just hours after her dramatic escape.

Kampusch, now 20, issued a statement Monday saying she wanted to contact Elisabeth to offer emotional and financial help.

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Associated Press Writer William J. Kole reported from Vienna.