London: Josef Fritzl planned to kill the family he held in a cellar in an acid bath to hide his crimes, he confessed to a teenage cellmate after his arrest.
The 75- year- old man raped his daughter Elisabeth up to 3,000 times in the 24 years he kept her locked in the basement of the family home and fathered seven children by her.
Arsonist Patrick Jakob, 19, who was released in the summer after spending three months locked up with the monster in St Poelten jail, Austria, revealed the man’s evil scheme.
"Fritzl told me he was tired of living two lives and wanted to rest in his old age,” the Sun quoted Jakob as saying.
"He said he had two choices - to let them all go and face justice, or kill them. He said he had considered how he would kill them and the best option would be an acid bath, so all traces of his secret family would be destroyed.”
"That way no one would ever know what he had done. He could make them all disappear. He had all the details worked out," he said.
The chilling confession shows how close Fritzl came to escaping punishment for the horrors he inflicted on Elisabeth, now 44, and the three incest kids who lived with her in the cellar.
The children are Kerstin, now 21, Stefan, 20, and Felix, seven.
Three more - Lisa, 18, Monika, 16, and Alexander, 14 - lived upstairs with Fritzl and his wife Rosemarie, 70, in Amstetten, 80 miles west of Vienna.
A seventh, Michael, died days after birth and Fritzl was charged with his murder.
Fritzl was arrested in April 2008 and is likely to spend the rest of his life in a psychiatric institution.
In March last year, Fritzl pleaded guilty to false imprisonment and incest, part guilty to rape and sexual abuse, and coercion - but not guilty to slavery and murder.
But after hearing Elisabeth`s testimony in court, he admitted everything.