Melbourne, May 5 : The sister-in-law of Joseph Fritzl, an Austrian man accused of holding his own daughter captive for 24 and fathering seven children with her, has described him as a “tyrant”.

The woman, who asked only to be identified as Christine R. to avoid public attention and throngs of journalists seeking interviews, said that Josef Fritzl had instilled a culture of fear at home due to which no one questioned of his daughter Elisabeth’s running away to join a cult, and abandoning three children on their doorstep.

"When he said it was black, it was black, even when it was 10 times white. He tolerated no dissent," the Daily Telegraph quoted Christine R. as saying during an interview, conducted at her home in Austria.

"Listen, if I myself was scared of him at a family party, and I did not feel confident to say anything in any form that could possibly offend him, then you can imagine how it must have been for a woman that spent so many years with him," she added.

She even revealed that her brother-in-law was jailed in for "a year and half" in connection with a 1967 rape conviction.

Christine R. said that that event was quite shocking for her sister Rosemarie.

She, however, said that Rosemarie still focused on keeping her family healthy, believing that “everyone makes a mistake”.

"You can surely imagine that a woman in such a situation would have been utterly broken and shocked over something like this," Christine R. said.

As time went on, she said, her sister’s relationship with Fritzl soured.

"As far I know no sex took place in recent years. I believe it was because of his prior conviction, and because my sister had been getting bigger. And in any case he never liked fat women," she said.

Christine R. even said that neither Fritzl nor Elisabeth ever hinted that something was disturbing about their relationship.

"He was just as strict with her as he was to every other child. There was nothing in particular that could lead you to say he was more intimate with her. From the child as well it never came out. She never confided in anyone," she said.

"My sister is apparently doing very badly and Elisabeth is not in the best shape either. I know my sister and when something is wrong with her children the world collapses. For sure, the world has collapsed for her," added Christine R., who said that she had received updates on the condition of her sister and Elisabeth from a "good source".

Fritzl, who has not been formally charged, faces up to 15 years in prison if he is ultimately convicted on rape charges. (ANI)