HunterF You are more forbearing than I would be, and I absolutely hate making scenes.
Stop agonising about it and start taking positive action, even if you delay going to a lawyer for the moment. If you act as though you are on top of things, this woman will stop blackening your character. If you creep out of the way of everyone who accuses you, you will appear to feel guilty.
Faced with that as I returned from my nice few days away, I would have taken a deep breath and replied,
"Rubbish! My mother left me half the house in her will. I looked after my father for XX years and he left me the other half! Anyone accusing me of stealing it had better watch out, as I am consulting lawyers about sueing for slander!
Turn on heel and stomp out.