A FATHER has confessed to imprisoning his daughter in a windowless cellar for 24 years and fathering her seven children, police have said.

Freed Elisabeth Fritzl, 42, told yesterday how she was held captive by her rapist dad Josef after he lied to relatives that she had run away.

Three of her children aged 19, 18 and five were kept in the dungeon with her and NEVER saw daylight.

Today Austrian police said it was one of the nations worst-ever crimes.

And police official Franz Polzer said the suspect managed to deceive everyone.

The police said Fritzl told investigators that he tossed the body of one of the children in an incinerator after the child died.

Officials told reporters that the mans daughter and the rest of her children have been placed in psychiatric care.

Mr Polzer, head of the criminal investigations unit in the province of Lower Austria, said: "(Fritzl) has now said that he locked up his daughter for 24 years and that he alone fathered her seven children and that he locked them up in the cellar.

Fritzl also admitted to burning the body of one of the children when it died shortly after birth, he said.

Mr Polzer said: "After the daughter, a son was born, then three more. This case was especially tragic because some children actually died.

"One twin did die and he got rid of it. He just burned it on the balcony."

The horror was only revealed after the 19-year-old fell critically ill and evil Josef was forced to take the girl to hospital.

Doctors found a handwritten note in unconscious Kerstins pocket. It was from her mum begging medics to save her daughter.

Baffled by the illness, the hospital launched an appeal for missing Elisabeth to come forward and provide her medical history.

Cops found the secret dungeon, which included a padded cell, when they raided 73-year-old Josefs home in Amstetten, eastern Austria. The tiny entrance accessible only via a coded electronic lock was behind a cupboard in the garage.

Josef who had finally freed his daughter and the two remaining children was last night under arrest.

Austrias shocked interior minister Guenther Platter branded it an unfathomable crime.

The three children forced to live with Elisabeth in the windowless 5½ft-high cellar were oldest Kerstin, Stefan, 18, and five-year-old Felix. The only light came from electric bulbs.

Three other kids Lisa, 16, Monika, 14, and Alexander, 12 were adopted by Josef after he told his unsuspecting wife Rosemarie that Elisabeth had mysteriously left them on their doorstep.

The seventh a twin died three days after being born and he burnt the body. Rosemarie was said to have had NO idea of the hellish scenes under her house.

Josef simply told her when he freed Elisabeth that their daughter had finally decided to come home.

Elisabeth, who emerged from her prison starving and pale, was described as greatly disturbed.

Local police chief Franz Polzer said: The total area of the hidden rooms was 80 square metres with four small bedrooms.

The floor was uneven and on the walls were posters. Everything is very, very narrow.

He said of the imprisoned children: When they came out yesterday with their mother, they saw the daylight for the first time in their lives.

Cruel Josef lived two floors above with his family and even rented rooms in the house to tenants.

Five of the children were last night receiving counselling.

Kerstin was fighting for life in intensive care with doctors still baffled by her illness. Josef is said to have told his family that Elisabeth ran away to join a sect in August 1984 and had kept in touch only with occasional letters.

She told cops her dad had abused her since she was 11 then in 1984 drugged her and locked her up.

Officers said in a statement: She was abused continuously during the 24-year-long imprisonment. This led to the children.

Josef and his wife had five OTHER sons and daughters besides Elisabeth and all the others are respected members of the community with families of their own.

Neighbour Anita Lachinger said of Josef: He seemed whenever you saw him like such a harmless old man.

No one would have guessed the truth.

The children adopted by Josef were said to have been unaware their mother, brothers and sister were in the cellar, which had only a small TV.

When they were discovered on the doorstep, letters from Elisabeth explained she had been unable to cope with them.

Josef had forced her to write them. All were taken in by Josef and his wife as foster or adopted children and went to school as normal.

Below ground, Elisabeth had to teach the other kids to speak. They got no education.

The episode is the THIRD recent captivity scandal to rock Austria.

In August 2006, teenager Natascha Kampusch fled an eight-year ordeal as a hostage in a cellar in Vienna. And in February last year cops found a Linz lawyer had locked up her three daughters for seven years.