Australian Erin Patterson can now be called a triple-murderer after a nine-week trial ended in a guilty verdict.

A jury has unanimously agreed the 50-year-old deliberately laced a beef wellington with death cap mushrooms, killing three members of her estranged husband's family.

She's also been found guilty of attempting to murder a fourth person, after a jury deliberated more than six days.

Australian correspondent Oliver Peterson says each charge carries a maximum penalty of life in prison.

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