This is why I would like to know what they all ate, including pies with berries and ice cream, and what they drank. Also, what was provided by the hostess, and what was brought by the guests as a gift. Did anyone get outside and treat themselves to wild berries in the garden?
Of course, 97% chance that it was the hostess. She had the means. She could have own interests, and not necessarily love ones. Divorce and money that (in all fairness) was hers but didn’t look so by Australian laws?
But then, I can see some other parties’ interests, and they might be conflicting, too. So unless someone is officially accused, let us wait.
It is an interesting case because much as the hostess, by all accounts, is odd (I read it as “awkward socially”, or “slightly eccentric”), she is a very smart woman, this is why the case is not easy.