The warring Rineharts - Australia's richest family - are at it again as the clan returned on Tuesday, June 24, to court in an attempt to find a trustee for the $5 billion family trust.

News.com.au reported that the feud turned for the worse when John Hancock, who wants his sister Bianca to replace their mum Gina as head of the trust, called his younger sister Ginia a moron, an oxygen thief and intellectually disabled.

Ginia has sided with her mother in the family feud, initiated by her three other siblings, but another sister Hope opted out of the war after she reached a multimillion settlement with her billionaire mum.

News.com.au quoted John as saying, "Tell Ginia to wear a bag over her head to cover up her genetic deficiencies." Previous reports indicated that the Rinehart siblings are jealous of Ginia, who in siding with their mum, got perks, while they are suffering financially after Gina cut them off from receiving monetary support from the family firm.

Asked by the court to comment on John's statement, Bianca said she did not approve of his language, but she defended John whom she said didn't want to see the family wealth "left to someone ... who is not up to it."

Bianca, 37, said Ginia's backing up their mum's recommendation to have an independent trustee appointed instead of her is useless because her youngest sister is "so lost in it."

She warned that having a corporate trustee could place at risk Hancock Prospecting's stake in Hope Downs because the agreement between the family-owned Hancock and mining giant Rio Tinto is that the firm must be owned and controlled by direct descendants of Australia's richest person.

Bianca's lawyers are expected to push that she is qualified to be a trustee since she was a director and employee of Hancock Prospecting and would be guided by expert advice from an accountant or lawyer.

Gina, in turn, has accused Bianca of leaking company documents to John. More on that in this video.

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