I think my MIL had a part in her daughters .. well

I (29F) was trying to help my s/o find justice for his sisters passing. His mother (64F) we’ll say Rona has been very loud and proud on social media about it since 2012. She never actually tried to find legal justice for her daughter. Well I found the funeral paper they give out, saw the person who did it (allegedly) was on there as “ loving boyfriend). Well fast forward to a month ago I had talk to the local DA of the area had it sent to the SBI for them to open the cold case up. I just told her, “ hey I got the SBI to take the cold case we can finally get her justice”.

Well you’d think a loving parent who has claimed they wanted justice for her daughter would be thankful and wanting to know more information right? No the exact opposite of that. She ran across a room got in my face and was screaming at the top of her lungs that she rebukes me on Jesus name and that she rebukes the demon inside me. Obviously I’m just standing there confused and frozen. The only thing that left my mouth was, “ you’re rebuking the wrong demon, go stand in the mirror and rebuke the right one”. She stopped I left. Later that night she went to Facebook and made a post about her daughter and how I was disrespecting the dead, and her family.. That I am a snake in sheep’s clothing..

I called my s/o and he was telling me how after I left she was asking where the money was her daughter had.. He said he froze and that’s when it clicked about the whole thing for him. He said that he didn’t know how to respond other than what do you mean? She then goes on to tell him her daughter had money before she passed and wanted to know where the money was. He had no idea what she was going on about.

To me this made me feel like with the reaction in person, then the reaction on Facebook (I screenshotted by the way) and the 21 questions about this “money” she played a part. This women is also a Covert Narcissist and is mentally insane and self medicating with what we are assuming is pills..

After this she has gone around tarnishing my name, saying I’m evil and want to destroy everyone’s peace. She tried to convince my s/o he needed to leave me and all kinds of mess. All I did was try to help get the justice her daughter deserved. She can easily manipulate the reality of time with her kids because they grew up in that kind of warfare. This started fights between me and my s/o. She’s also caused a lot of fights between us because she can easily get it their heads. I’m not a bad person but not a perfect person either. What did I do wrong?