The Daily Telegraph reported Fritzl, 73, wanted to turn his Amstetten, Austria, home into a tourist attraction to raise money for his family.

His sister-in-law evealed Fritzl's alleged plan in an interview with the Austrian tabloid Oesterreich Saturday.

"He actually wanted to make a tourist attraction out of his house with the dungeon where he kept Elisabeth, and charge 10 euros for entrance," she said. "It is completely mad. The family was supposed to get the proceeds, but, naturally, all of them rejected his 'business' proposal."

Fritzl, 73, has confessed to imprisoning and sexually abusing his daughter Elisabeth, 42, in a bunker beneath his home. She gave birth to seven of her father's children.