I’m so sorry that you’re going through this. Might be worth getting a gopro or a cheapo sound recorder just in case, but at some point, you need to start taking care of yourself before you can look after her.

Obviously she's realised that starvation will slim her down quite quickly and if if you're arrested she'll be doing that.

You should tell her that if you go to jail, she'll have to order that food to be delivered to her house. Hmm? Maybe don't give her that idea.

I mean, if she's willing to lie to the police/lie in a way that gets the police called on you, why are you still interacting with her in any way? That's basically her telling you that she would rather see you in jail than caring for her, so take that as a sign to leave her to sort her own mess out. Like, I get she's your mother and disabled and needs help - But why does that fall on you, and only you? At the very least, limit your interaction to something like calling the public assistance line for her, and then letting them handle anything else from that point on - If she is too belligerent and delays getting help from them because of that, it's officially someone else's problem to solve. It sounds heartless, but at the same time, she's not exactly sounding terribly endearing herself. You don't need to endure abuse of any kind just because you're related to someone, nor because they themselves need help as well. There are professionals out there that can deal with these sort of things with the proper emotional distance, instead of all the emotion that comes from having to deal with an abusive relative. It's not about punishing her or anything. It's about protecting yourself. You deserve that much, I'd say.

If you can’t move out, document her behavior. If you can, do so and leave her to figure it out. Some people need a wake up call.