I was thinking she might diffuse suspicion by using a couple of different methods of killing her targets. Get some of the drinkers with some methanol "vodka", hit Hitler and several other key people with botulinum toxin, and give the b-listers rabies, possibly releasing a non-rabid but aggressive animal into the party as a cover story. (other suggestions are still welcome)
I was thinking that rabies likely would not be detectable as murder at that time. We can likely collect concentrated live rabies viruses in a way they probably couldn't have in the '30s, so I don't know if it would have *occurred* to anyone that someone could murder someone else by spiking their food or beverage with rabies.
But what I can't find is how reliably rabies can be *transmitted* that way. Everything I'm finding does seem to say that getting still-wet saliva in your mouth from a rabid animal counts as exposure to rabies, but I'm really not sure how likely one is to actually be infected by it. Anyone else know?