I had a similar thing happen with an ex friend. Back in high school she used to viciously bully people anonymously online and unbeknownst to me had told a lot of people it was me. I found out a couple years after high school but the damage was already done. The people who were bullied I reached out to and they believe me (I'm actually on good terms with them).
However, I didn't know what was going on and when I did find out I didn't realize the extent of the damage. Over 6 years I lost all of our mutual friends which was the majority of my friend group. My reputation was so damaged I would go to parties and people would come up and say horrible things to me. They would warn people about me so I was never able to make new friends with anybody within that larger friend circle. I was even verbally attacked at dinner by several people for being a horrible person while one of my best friends sat back and watched while I begged for him to tell them I didn't do it (he knew the truth but kept quiet).
It honestly happened so slowly and over such a long period that I truly begun to think they were right and I was a horrible person. It was only when I moved across the country for a job my life started to get better. But this summer I found out she had my passwords (I can think of several reasons she had them and it's my fault for not changing my password since high school) when she took over my Facebook. I managed to get it back after a couple days but she had added several people. I don't know exactly what she did but I'm assuming she sent some messages and deleted them on my end so I couldn't see. I even had someone try to hack onto my gmail account through a phishing link a mutual friend sent me. Also during this same time period I received a shit ton of DMs on instagram from several fake accounts threatening me.
Long story short I changed all my passwords, put in a shit ton of security and sent her a message saying I was going to file a lawsuit if she continued with this behavior. It's stopped for now.
I honestly think you should reach out to your friends and try to communicate your side of the story. I made the mistake in thinking my friends would ask me my side of the story if something happened instead of just believing her. There's also the issue of people ganging up against you. I would prepare myself to the fact you may end up losing your old friends. Hopefully since Maria has become more visible with her crazy you can do more damage control. It's crazy that someone else went through something similar! Although Maria seems a lot more dangerous than my ex friend.