Erin Patterson's conviction for the deaths by poisoning of her estranged husband's relatives has prompted fevered speculation across Australia about her motive.

The Australian woman was convicted of murdering three elderly relatives of her estranged husband with a meal laced with poisonous mushrooms, and attempting to murder a fourth, in a case that gripped the country.

Erin Patterson has been found guilty of murdering three people with a toxic mushroom lunch following a marathon ten-week trial in Victoria. Justice Christopher Beale sent the jury to deliberate last Monday, urging them to resist feelings of bias.